Make postmarketos-base as tiny as possible

Today @craftyguy, @minlexx, @dylanvanassche, @MartijnBraam and I discussed the firewall topic (#1024 (closed)), and concluded that it makes sense to install nftables + the firewall package by default. However, for mainlining, it is desired to have postmarketos-base as small as possible.

So we also came up with the following:

• Wait until !2060 (merged) (firewall) is merged
• Create a postmarketos-base-ui subpackage of postmarketos-base
• Let every UI depend on postmarketos-base-ui
• Move all depends that are not absolutely essential to boot the device from postmarketos-base to elsewhere.
• Keep:
  • openssh: very much needed for debugging unless serial is an option (and even then ssh is more convenient)
  • postmarketos-mvcfg: can be called by all packages to fix configs, and this is just two shell scripts without depends
  • sudo: we don't set a root password in pmbootstrap, so having sudo working is required to gain root access
  • eudev: essential for loading kernel modules
• Move to postmarketos-base-ui:
  • chrony
  • dbus
  • postmarketos-config-nftables
  • haveged
  • shadow
  • util-linux
  • wpa_supplicant
  • wireless-regdb
• Move from postmarketos-base to all UIs depending on NetworkManager (that's why it was added in !1438 (merged), but it was not moved in !2174 (merged)):
  • dnsmasq
• Move to postmarketos-mkinitfs:
  • cryptsetup: postmarketos-mkinitfs calls cryptsetup directly to find the encrypted partition IIRC

CC: @Minecrell