Draft: pmb.parse.kconfig: prefer binderfs for Waydroid

The usage of binderfs used to be blocked by Anbox support, but that has been unsupported for almost a year soon according to it's own wiki page: https://wiki.postmarketos.org/wiki/Kernel_configuration#CONFIG_BINDERFS

With this Waydroid can dynamically make the binder nodes when it's launched instead of them always being there upon booting even if you never install or use Waydroid. Keep fallback to static binder nodes on kernels <5.0 where binderfs didn't yet exist (at least on mainline Linux kernels).

Marking as a draft for now because the following need to be done:

• Fix pytest -vv ./test/test_kconfig_check.py to pass CI
• Create a pmaports MR adapting all kernel packages that check the Waydroid options (pmb:kconfigcheck-waydroid and pmb:kconfigcheck-community)
• Figure out how to proceed with minimal disruption to existing working Waydroid installations: my theory from previous experience is that sudo waydroid init -f will need to be ran due to change in the kernel binder configuration which have to be reflected in /var/lib/waydroid/{waydroid.cfg,lxc/waydroid/config_nodes} or else Waydroid won't start anymore since it still tries to use the old binder nodes; I'll have to test how this goes locally first.