Back-end:
* update alerting module
* update GetSecretKeysForContactPointType to extract secret fields from nested options
* Update RemoveSecretsForContactPoint to support complex settings
* update PostableGrafanaReceiverToEmbeddedContactPoint to support nested secrets
* update Integration to support nested settings in models.Integration
* make sigv4 fields optional
Front-end:
* add UI support for encrypted subform fields
* allow emptying nested secure fields
* Omit non touched secure fields in POST payload when saving a contact point
* Use SecretInput from grafana-ui instead of the new EncryptedInput
* use produce from immer
* rename mapClone
* rename sliceClone
* Don't use produce from immer as we need to delete the fileds afterwards
---------
Co-authored-by: Gilles De Mey <gilles.de.mey@gmail.com>
Co-authored-by: Sonia Aguilar <soniaaguilarpeiron@gmail.com>
Co-authored-by: Matt Jacobson <matthew.jacobson@grafana.com>
