Change default session log directory to ~/.local/state (#859)

This addresses #808 and #823 conclusively for all parties.
- It requires no additional directory creation.
- It does not impact users who do not have a problem.
- It adds additional documentation detail in both the bug template and
the readme to help users who *are* having a problem.
- Fulfills the spirit of the [XDG Spec(https://specifications.freedesktop.org/basedir-spec/latest)
but not in practice as `$XDG_CONFIG_HOME` and `$HOME` and the associated
logic are not implemented. `~/.local/state` is the fallback location.

In particular, the spec indicates:
> It may contain: actions history (**logs**, history, …)

Reviewed-on: https://codeberg.org/fairyglade/ly/pulls/859
Reviewed-by: AnErrupTion <anerruption@disroot.org>
Co-authored-by: Corey Newton <corey.newton@zenoprax.com>
Co-committed-by: Corey Newton <corey.newton@zenoprax.com>

readme.md

@@ -57,6 +57,10 @@ managers, all of which you can find in the sections below:
 
 [X11 environments](#supported-x11-environments)
 
+Logs are defined by `/etc/ly/config.ini`:
+ - The session log is located at `~/.local/state/ly-session.log` by default.
+ - The system log is located at `/var/log/ly.log` by default.
+
 ## Manually building
 
 The procedure for manually building Ly is pretty standard: