feat: move storage path setting to configuration file

- change default storage path to /srv/libretime
- remove music dirs table
- use /tmp for testing storage
- storage dir should always have a trailing slash

shared/libretime_shared/config.py

@@ -109,6 +109,11 @@ class GeneralConfig(BaseModel):
     api_key: str
 
 
+# pylint: disable=too-few-public-methods
+class StorageConfig(BaseModel):
+    path: str = "/srv/libretime"
+
+
 # pylint: disable=too-few-public-methods
 class DatabaseConfig(BaseModel):
     host: str = "localhost"