Refactor service agent management (#2423)

* Service agents script

* Service agents update

* WIP

* Update script and terraform

* Fix tests

* Fix linter

* Update docs

* Bring back pf example inventory

* Fix tests

* Fix more tests

* Fix tests

* Use dataclasses for build_service_agents.py

* Remove unneeded field() from build_service_agents

* Re-enable CMEK depends_on in project outputs

* Update tools/requirements.txt

* Enable storage in GCS example projects

* Fix tests

* Add CMEK Service Agents dependencies for services

* Fix typos and data platform cmek

* More typos

modules/net-vpc/README.md

@@ -231,7 +231,7 @@ module "vpc-host" {
     module.service-project.project_id
   ]
 }
-# tftest modules=2 resources=13 inventory=shared-vpc.yaml e2e
+# tftest modules=2 resources=14 inventory=shared-vpc.yaml e2e
 ```
 
 ### Private Service Networking