This adds validating admission hooks to enforce the requirements on AlertRules and RecordingRules that are currently enforced through the provisioning service and storage mechanisms in preparation of a consistent validation in both legacy storage and unified storage. It also adds a mutating admission hook to the app to ensure that folder annotations and folder labels are kept in sync so we can perform label-selector lists.
This renames `data` to `expressions` for clarity in the rules apis.
Also makes certain fields that are redundant optional in the case of pure expressions, so that users don't have to specify them when they are not needed (e.g. not datasource queries).
The first version of the app platform apis for alerting rules, including AlertRule and RecordingRule definitions.
Co-authored-by: William Wernert <william.wernert@grafana.com>
Moustafa Baiou
Austin Pond
Ryan McKinley