[Provision alignment] Provision a free plan (downgrade)
### Problem
The current provisionings for GitLab.com and SM/Dedicated follow markedly distinct approaches. While SM/Dedicated relies on licenses (license key or file) to contain all needed info, GitLab.com relies on multiple syncs for a namespace.
To align the provision between the deployment types, the GitLab.com provisioning will be aligned to be similar to the SM/Dedicated. The current multiple syncs to GitLab.com will be replaced by a single sync for a namespace which includes all needed information at once. Each sync will be stored in the database on the CustomersDot side for easier auditing. These records will follow a similar behavior as the license generation for SM/Dedicated and only create a new entry for a sync if the data/info for the new sync has changed compared to the last sync. Timestamps for each sync will still be stored for a better insight into the sync frequency.
### Proposal
In other issues, the base for the new provision workflow was implemented. It should currently only cover a single namespace sync of the base product. With https://gitlab.com/gitlab-org/customers-gitlab-com/-/issues/12221+, the params generator for a free plan was added.
The namespace provisioning should now be able to provision a free plan (downgrade).
### Result
Provision a free plan.
issue