Add reference to QtGreet
Note that sway-run should be executable

This also fixes a minor naming inconsistency.
Replace $SHELL with /bin/sh
recommend making config world readable rather than setting owner

There is no secret material that needs to be unreadable except to the
daemon, but if there were, the current instructions never recommended
setting a locked down mode.

The daemon doesn't need write access either.

Recommending chown rather than making the config world readable as is
typical for bog standard system configs, is confusing and inconsistent
with e.g. the in house AUR packaging. It also might be erroneously
interpreted as a requirement, which is challenging for packaging systems
that don't support distributing files/directories owned by non-root
Document SELinux error
Warn against full themes
Mention gtkgreet stylesheet
Mention that cage allows VT switching with -s
Expand a bit on Sys(ENOMEM)
Add mlockall error to the troubleshooting guide
Added tuigreet to known greeters list.
Mention initial session
Update for new config file format
Add wlgreet help
Add greeter list
Link to repositories
Explain boring default session
Add troubleshooting step for greeter not starting
Explain recommended use of wrapper scripts