add route to fetch album color

app/api/colors.py

@@ -0,0 +1,13 @@
+from flask import Blueprint
+from app.db.store import Store
+
+api = Blueprint("colors", __name__, url_prefix="/colors")
+
+
+@api.route("/album/<albumhash>")
+def get_album_color(albumhash: str):
+    album = Store.get_album_by_hash(albumhash)
+
+    return {
+        "color": album.colors[0]
+    }