services: Reorganize services, detect X

Detect X autostart a bit better with a separate service. The service
relies on a shell script which searches for a socket which X creates on
startup and only finishes when it finds the socket succesfully.

This makes services which need X to start successfully a bit more
robust, and while it can still break if X takes too long, it should be
more stable now.

Finally, services can restart more quickly when ended since they don't
require the 2+ `RestartSec` option to be present anymore to successfully
start.

services/.config/systemd/user/dropdown-todo.service

@@ -1,13 +1,13 @@
 [Unit]
 Description=Todo.md floating vim instance
-After=display-manager.service
+Requires=x-started-confirm.service
+After=x-started-confirm.service
 
 [Service]
 Type=simple
 # workaround to allow relative executable invocation (i.e. current users' home dir)
 ExecStart=/bin/bash -c 'alacritty --title "dropdown-todo" --class "Alacritty,scratchpad" -e nvim -c ":set nonumber norelativenumber noshowmode noruler laststatus=0 noshowcmd shortmess=F | :Limelight" %h/documents/records/todo.md'
 Restart=always
-RestartSec=2
 
 [Install]
 WantedBy=default.target