Draft: tablet-x{86,64}uefi: move to community

I would like to see images produced for these "generic" tablet devices, and for them to have stable pmOS releases.

This is currently WIP since I think the following should be addressed or changed first:

• "standardize" the bootloader between the two packages

  • grub seems like the best candidate, and is currently the "standard" between them, but it's messy.
  • systemd-boot (as a standalone efi app) or something like it would be ideal (imho)

• combine the two packages into a single package, using deviceinfo_arch (or something like it) to support any differences

• decide to support only linux-lts? or linux-lts + linux-edge?

  • update linux-edge is in stable... but I think lts should also be an option for both (it's currently just an option for one of them)