First of all, thank you all for your numerous replies on my last post! I would not have expected such an amount of positive responses, you made my week!
Now for the update: I'm not sure why I did not think of this earlier, but with your input I realized that local playback is a very nice feature to have. (I'm using it right now!)
You can now scan a local folder on you Raspberry Pi in Raveberry's settings and all its audio files will automatically be added to the database. Then they will be suggested when you start entering them in the input box. You can even create Playlists for every Folder, allowing you to enqueue whole albums at once!
View the new version on Github or download it from Pypi. After you upgraded your package with pip3 install -U raveberry you can upgrade your system installation by simply rerunning raveberry system-install. Your database will be left untouched if you don't specify a backup file in your config.