This separator was introduced to better distinguish the numbers of the
battery percentage and the clock. As the "power-manager" plugin was moved
left of the "pulseaudio" plugin, this separator isn't needed anymore.

The clock becomes "plugin-8" now. The plugin ID numbers of the lower panel
weren't changed to avoid upgrade issues with the launchers placed there,
as they additionally have local data stored in ~/.config/xfce4/panel.

The previous font size of 8 is hardly readable on the growing number of
high-resolution screens. Therefore increasing it, but not too large, still
considering the limited space of older low-resolution screen devices.

Additionally, replace the "digital-format" string setting by the "digital-layout"
type setting. The result is the same but it's more fail-safe for future Xfce
updates.

The "power-manager" shows battery percentage. Those numbers are close to
the clock, which needs a close look to distinguish the numbers. Moving the
"power-manager" plugin left of the "pulseaudio" plugin slightly disturbs
the harmony of having all numbers at the right-hand side but separating them
increases readability.

Now "power-manager" becomes "plugin-6" and "pulseaudio" becomes "plugin-7".

The icons of the status tray plugin were rather small and arranged in two
rows. This was due to the upper panel being quite crowded and increasing
their size causes difficulties on devices with small screen. On the other
hand, more and more touchscreen devices with high resolution show up in
postmarketOS, where it hardly possible to hit the tiny icons.

Being able to hit the "onboard" icon is crucial for touchscreen usage because
this calls or hides the virtual keyboard in situations where it doesn't show
up automatically. But also the network-manager icon the the bluetooth icon are
important icons that should be accessible.

Increasing their icon size is a compromise between facing the growing number
of high-resolution touchscreen devices and preserving usability on older low-
resolution touchscreen devices.

The "backdrop" background picture handling was extensively reworked in
Xfce 4.20 [1]. Unfortunately, the default backdrop image gets set when
compiling the package [2]. User-specific changes are stored in local config
file "xfce4-desktop.xml" by property "last-image" per workspace. However,
workspaces are assigned to monitors and they have hardware-specific names.
Deriving local monitor preferences from generic ones worked before but it
doesn't seem to work anymore.

Summarizing, currently there seems no way to set the postmarketOS wallpaper
as the default backdrop image.

[1] https://gitlab.xfce.org/xfce/xfdesktop/-/commit/edb653c37038fcfce61c424ce841c4f5aa0faaf1
[2] https://gitlab.xfce.org/xfce/xfdesktop/-/blob/xfdesktop-4.20.0/meson.build#L112

Change theme to "Greybird" explicitely. It was used as the default theme in
postmarketOS Xfce4 already, but upstream changed the default to "Adwaita" [1].

[1] https://gitlab.xfce.org/xfce/xfce4-settings/-/commit/d1a04d48c1a78805faa530e453e3c0733944d025

These lines were implemented in the xfce4-phone config to simplify the
display power behavior. They set the number of seconds until Xfce4 power
manager reduces the display brightness.

The idea is to disable the brightness reduction by Xfce4 power manager
because this can confuse the tool "brightnessctl", which offers a service
to save and restore the display brightness across boots.

A value of 0 did not achieve the desired effect. The display brightness got
reduced nonetheless.

It turned out that the minimum time is 10 secs. Because of that a value of
9 disables the brightness reduction feature.

This is supposed to avoid too much of a hassle when enabling brightnessctl
in postmarketOS to save and restore display brightness over boots.

With these settings the display just switches off after 2 mins on battery
or 5 mins with power plug connected. Further settings like reducing the
backlight after a while, display blanking and display sleeping are disabled,
as they may cause issues when handling the backlight. Users can nonetheless
enable those features in the power settings if desired.

This makes double-clicking on touchscreens easier where needed.
It shouldn't hurt laptop usage too much.

Tooltips currently don't work well with touchscreens in GTK. They may show up
undesired, don't go away and hinder the interaction.

The GTK setting "gtk-enable-tooltips" to disable is deprecated since 3.10,
unfortunately.

A workaround to get rid of tooltips is setting their opacity to zero.
Additionally set the font size to zero as well to reduce the area that
the now transparent tooltip covers.

In xfce4-whiskermenu-plugin 2.8.0 the storage location for the menu settings
was moved to xfconf. They are now part of the xfconf file of the panel.

Additionally, the default positioning of the menu elements were changed.

This commit restores the whiskermenu layout as they were before in
postmarketOS Xfce4.

This is a preparatory step for moving the whiskermenu settings to xfconf,
as it's required by xfce4-whiskermenu-plugin 2.8.0.

They are equal to the default desktop files in /usr/share/applications.

Place the panel default to the same location like upstream configs in
/etc/xdg/xfce4.

The dpi value was implemented with the idea to make it overridable by
device package post-install scripts. This approach was wrong, as it's
not a clean way to override configs. Let's remove the dpi value again.

It is the same like in upstream config in /etc/xdg/xfce4. Therefore
no need to specify it again.

No need to have a full config file. Configs that differ from upstream
configs are sufficient.

No need to have a full config file. Configs that differ from upstream
configs are sufficient.

The keyboard shortcuts are currently the same like the upstream
default. Therefore there is no need for a custom config file.

When removed, default settings will be used.

Implementing the font DPI in the configs does not change anything
actually. However, having the value in the configs allows it to be
overwritten by device packages post-install scripts. That way devices
with high resolution screens can be assigned a larger text
representation on Xfce4 installation.