Move configuration to separate directory

[Adrian Gaborek (Layfully)]

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To allow symlinking configuration directory I'd like to move all configuration related files to separate directory. Here I'll try to accomplish that without breaking changes i.e for new installations use the new directory directly, for existing ones move settings to the desired directory and use them from there. I try to follow the existing codebase style and hopefully will be able to contribute this feature to the project. I'll keep it draft until I think it's ready for review, will take me some time as I plan to spend 30 minutes to - 1 hour on it when I have free time.

Closes #3285

[Martí Climent (marticliment)]

The only requirement I would say is that it must be backwards compatible, in the sense that settings must be automatically migrated to the new folder, with the process being transparent to the user

[Adrian Gaborek (Layfully)]

Hey Martí Climent (@marticliment), I think it's ready for review. I tested it manually, and at startup, all existing configuration files are successfully moved to the Configuration directory. I also wrote tests to cover both fresh installations and scenarios with existing configurations.

Now that configuration files are stored in a separate directory, we could consider adding a setting to allow users to specify a custom path for the configuration directory. This would give them more flexibility in managing their configuration files.

[Martí Climent (marticliment)]

Now that configuration files are stored in a separate directory, we could consider adding a setting to allow users to specify a custom path for the configuration directory. This would give them more flexibility in managing their configuration files.

This could work in the same way UniGetUI changes settings location when in portable mode

[Adrian Gaborek (Layfully)]

Do you mean I should extend something there? My thoughts were just an idea if someone wanted to have it. Currently I'd be happy with what I've implemented if possible

[Martí Climent (marticliment)]

Currently I'd be happy with what I've implemented if possible

Don't worry then, I will do it eventually. I will test, review and merge soon