Add option for custom sort order

[dehlen]

I think it would be nice to give the user the option to apply some custom sort logic. This way the user could for example add all running builds to the top or sort alphabetically. If you think this could be part of this project I am happy to help out with a PR.

[dehlen]

I implemented an option to sort the branches. For now I added this to the preferences dialog. Because of that currently changing the sort order only works by going into the preferences -> selecting the desired sort order -> Clicking Apply -> Refreshing the Build View. I could refresh the build view when apply is clicked but I am not sure that is a behavior you would want?

I guess a better UX would be to add custom NSMenuItems or a toolbar button to change the sorting order. If I would add the sortOrder as a Published variable to the settings store instead of the current way the SettingsStore reads/writes its data I could also update the sort order as soon as a selection is made, instead of waiting for the builds to refresh.

What do you think @stefanengel ? Do you have any preferences? Also is this a feature you would want to see in Lumina altogether?

Attached is a screen video of my current implementation (.zip file because GitHub does not allow video files).
Sorting.zip