Moves system-level operations (auth, billing, admin) to use the
/metadata endpoint instead of /graphql.
This cleans up the endpoint separation so /graphql is purely for core
objects (Company, People, etc.) and /metadata handles all system
operations.
Part of prep work for webhook/API key core migration.
# Content
- Introduce the `workspaceUrls` property. It contains two
sub-properties: `customUrl, subdomainUrl`. These endpoints are used to
access the workspace. Even if the `workspaceUrls` is invalid for
multiple reasons, the `subdomainUrl` remains valid.
- Introduce `ResolveField` workspaceEndpoints to avoid unnecessary URL
computation on the frontend part.
- Add a `forceSubdomainUrl` to avoid custom URL using a query parameter
Félix Malfait