Add live reloading of configuration file

[davfsa]

This also removes the need for a file with all the available configuration and a shadow configuration file.

Additionally, added several improvements:

1. Reduce I/O on initial configuration loading by only reading file once, instead of once per option (scary! Hyprpanel has a lot of options)
2. Remove unnecesary back and forth events when editing configuration

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There were also old references to a "cache file", which is no longer a thing since the Astal migration, so renamed those too

[davfsa]

Kind of closes #381, as it is now way nicer to edit these types of configuration, but im not sure :)

[Jas-SinghFSU]

Nice! I'll review this over the weekend when I get more time.