Add more service implementations

Co-authored-by: Patrik Oldsberg <poldsberg@gmail.com>
Co-authored-by: blam <ben@blam.sh>
Co-authored-by: Johan Haals <johan.haals@gmail.com>
Signed-off-by: Fredrik Adelöw <freben@gmail.com>

packages/backend-plugin-api/package.json

@@ -34,7 +34,8 @@
     "start": "backstage-cli package start"
   },
   "dependencies": {
-    "@backstage/config": "^1.0.1"
+    "@backstage/config": "^1.0.1",
+    "@backstage/backend-common": "^0.14.0"
   },
   "devDependencies": {
     "@backstage/cli": "^0.17.2-next.0"