greetd: look into regreet alternatives

[aemogie]

because regreet feels very clunky and unpolished

gtkgreet

pros:

• customisation with gtk css

cons:

• wayland client so needs cage or other compositor

tuigreet

pros:

• no flashing ttys, like you have with regreet because everything is a tty

cons:

• no custom fonts
• no background images

raygreet

pros:

• uses linux drm directly, not a wayland client

cons:

• need to figure out how to build zig projects
• feels very wip

ddlm

pros:

• again, no wayland client. but this uses fbdev instead

cons:

• very minimal
• might have to patch it to customise