Code Improvements for Projects :: Infra :: Google Cloud

Purpose

This MR introduces code fixups from !73896 (merged) and !74880 (merged) which were considered "out-of-scope" of those MRs.

Things were considered out-of-scope because:

1. They either didn't serve the purpose of the MRs i.e. they had nothing to do with the creation of service accounts frontend or backend, or
2. It was considered worth merging and creating a future issue / MR as everything is disabled behind a feature flag i.e. merge small MRs rather than a single giant MR.

Changes introduced

• Feature flag incubation_5mp_google_cloud bound to Project. This allows for easier testing on gitlab.com where the feature flag may be enabled for select projects.

• service_accounts is an active route for google_cloud menu item. This expands the appropriate project sidemenu item when creating a service account

• Introduce a top level app.vue component. Achieves consistency with a majority of frontend code in the repo where a single route with a single entry point serves multiple templates. Instead of routing the frontend in index.js use a top level component to render the appropriate screen.