fix client: download fallback to github release client

+ add fallback release version data to version.txt
+ move classproperty class to utils
+ update Dockerfile to install from source using pip install
+ move version info to Metadata class in settings.py

src/swingmusic/api/settings.py

@@ -1,5 +1,4 @@
 from dataclasses import asdict
-from importlib import metadata
 from typing import Any
 from flask_openapi3 import Tag
 from flask_openapi3 import APIBlueprint
@@ -9,6 +8,7 @@ from swingmusic.api.auth import admin_required
 from swingmusic.db.userdata import PluginTable
 from swingmusic.lib.index import index_everything
 from swingmusic.config import UserConfig
+from swingmusic.settings import Metadata
 from swingmusic.utils.auth import get_current_userid
 
 bp_tag = Tag(name="Settings", description="Customize stuff")
@@ -102,7 +102,11 @@ def get_all_settings():
             config[key] = sorted(list(value))
 
     config["plugins"] = [p for p in PluginTable.get_all()]
-    config["version"] = metadata.version("swingmusic")
+    config["version"] = Metadata.version
+
+    if config["version"] == "0.0.0":
+        # fallback to version.txt (useful for docker builds)
+        config["version"] = open("version.txt", "r").read().strip()
 
     # only return lastfmSessionKey for the current user
     current_user = get_current_userid()