With the arrival of new members to the data team, I've redesigned a bit the game of roles and users in the DWH.
This PR modifies the infra script to include the commands that should be run to end up in today's state of the DWH should we ever have to redeploy from scratch.
It's not fully perfect since it requires some statefulness (personal users of data team members, existing `sync_`schemas made by airbyte, etc). But it does create all necessary roles and the most important users. And it explains the general philosophy.
Related work items: #16911
