docs: use custom templates for ML resource docs

[sd2k]

Using custom templates, similar to SLO and Synthetic Monitoring,
allows us to include multiple examples in the documentation of
each resource, along with comments for each resource.

[github-actions]

In order to lower resource usage and have a faster runtime, PRs will not run Cloud tests automatically.
To do so, a Grafana Labs employee must trigger the cloud acceptance tests workflow manually.

[sd2k]

The CI failures are due to some SLO tests failing; I've raised it in Slack.