* DatabaseService resource: client and server CRUD
In the context of Teleport Discover, we must be able to known if there's
any DatabaseService available to proxy a given Database resource.
If there's none available, we will offer a script for the user to run
and install a DatabaseService which proxies the desired Database
resource.
By DatabaseService, we mean the process that Teleport binary manages
when the `teleport.yaml` config has the following section:
```yaml
db_service:
enabled: "yes"
```
To accomplish this we are creating a new resource: DatabaseService.
The UI will fetch all DatabaseServices and check if there's any
ResourceMatcher that matches the DatabaseLabels.
A previous PR created the DatabaseService resource.
This PR creates all the necessary CRUD operations:
- Add Service to manage DatabaseServices resources in the backend.
- Add GetAll, Upsert, Delete and DeleteAll operations to Client.
- Add DatabaseService support to ListResources.
- Add WebAPI endpoint to list DatabaseServices using ListResources.
The next PR will add the heartbeat mechanism to the DatabaseService
process.
Marco André Dinis