Move an existing tenant to a catalog

A tenant built by hand can be moved under a catalog without recreating anything.

Export. In Remote catalogs, use Export this tenant. The zip holds one folder per kind and one YAML file per entity, in the envelope format:
```
team/team-weather.yaml
api/api-weather.yaml
usage-plan/plan-weather-free.yaml
keyring/keyring-weather.yaml
api-subscription/subscription-weather.yaml
cms-page/page-weather-home.yaml
api-documentation-page/page-weather-start.yaml
```
By default only the entities managed by no catalog are exported; tick the option to export everything. The admin API and the CMS API are never exported, nor their plans, their subscriptions and the keyrings that only hold those: Daikoku creates them with each tenant. The files hold the credentials as stored (keyring keys, headers, testing credentials): keep them somewhere safe. The same export is available on the admin API: GET /admin-api/remote-catalogs/_export?all=false.
Commit the files in a repository. Rearrange them as you like, for instance in team folders.
Create the catalog on that repository, with Adopt existing entities on, and recursive (or One folder per team) since the files are in subfolders.
Test. The dry run must report the entities as updated and no error. An entity described in the files but already tagged by another catalog is refused: never taken over.
Deploy. Every entity is now tagged with the catalog.
Turn Adopt existing entities off. From now on, an untagged entity described in the files is refused again, which protects the entities created by hand afterwards.