Draft: Implement xdg-activation v1 protocol plugin

[kode54]

This is a draft, in case it is desired to implement the XWayland equivalent of this protocol into the same plugin.

[ammen99]

After looking at the sway pr, I see that the launcher contexts are optional (we don't have that concept in wayfire yet so it can be left aside).

Also, leaving a few comments, even though this is a draft :)

[ammen99]

I think something went wrong, because I do not see any changes since last time ..

[kode54]

Oh, that's ducking stupid. I somehow managed to amend commit without staging the new files.

[ammen99]

Thanks!