[fix] Revert mongodb to 8.0.x (#554)

Unifi does not like 8.2.x - fails with something like this:
```
{"t":{"$date":"2025-12-
  03T03:37:48.012+00:00"},"s":"F",  "c":"CONTROL",  "id":20573,   "ctx":"initandlisten","msg":"Wrong mongod
  version","attr":{"error":"UPGRADE PROBLEM: Found an invalid featureCompatibilityVersion document (ERROR:
  Location4926900: Invalid featureCompatibilityVersion document in admin.system.version: { _id:
  \"featureCompatibilityVersion\", version: \"7.0\" }. See https://docs.mongodb.com/master/release-
  notes/8.0-compatibility/#feature-compatibility. :: caused by :: Invalid feature compatibility version
  value '7.0'. Expected one of the following versions: ''8.2', '8.1', '8.0'. See https://docs.mongodb.com/
  master/release-notes/8.0-compatibility/#feature-compatibility.). If the current
  featureCompatibilityVersion is below 8.0, see the documentation on upgrading at https://docs.mongodb.com/
  master/release-notes/8.0/#upgrade-procedures."}}
```

Following [the procedure for

8.2](https://www.mongodb.com/docs/upcoming/release-notes/8.2-upgrade-standalone/),
this includes the feature version
compatibility update command. Not sure why 8.0.x didn't fail.

Author: robarnold

kustomization/components/unifi-network-application/configmap/generate-init-mongo.sh

@@ -28,4 +28,5 @@ db.getSiblingDB(\"unifi_stat\")
     roles: [
       {role: \"dbOwner\", db: \"unifi_stat\"}
     ]
-  });" > /docker-entrypoint-initdb.d/init-mongo.js
+  });
+db.adminCommand({setFeatureCompatibilityVersion: '8.0', confirm: true})" > /docker-entrypoint-initdb.d/init-mongo.js

kustomization/components/unifi-network-application/kustomization.yml

@@ -13,7 +13,7 @@ images:
   - name: lscr.io/linuxserver/unifi-network-application
     newTag: 10.0.160@sha256:8d7c822076305456ac16b91604e34e2fa129969b74c70a7c566914fecd9ae87e
   - name: mongo
-    newTag: 8.2.2@sha256:7245ffb851d149dbfac67397caf91bae4974d899972f9fd1d8985fc6eea3c13d
+    newTag: 8.0.15@sha256:bc0c381d51fb4a316a8f420bf35b6c29ca45167cdea4ec1df4e6e64c9b90022a
 resources:
   - statefulset.yml
   - serverstransport.yml