Closes#198646
* The options `password`/`basicAuthPassword` were removed for
datasources in Grafana 9. The only option to declare them now is to use
`secureJsonData`.
* Fix description for contactPoints provisioning: when using file/env
providers, nothing will be leaked into the store.
* Fix regex in file-provider usage check: it's also possible to either
use `$__env{FOO}` or `$FOO` to fetch secrets from the environment.
* Fix warning for datasources: `password`/`basicAuthPassword` was
removed, also check for each setting in `secureJsonData` if
env/file-provider was used (then no warning is needed!).
4ec456b725