Refactor: Common opts structs and ResyncPeriod

[Baarsgaard]

This PR takes the first step towards refactoring the reconciliation loops for all CRs.

I've added a GrafanaCommonOptions struct which embeds the Common Options fields as a singular struct.

This means that all CRs will use the same comments, rules for CRD generation/deserialization, and default values.
This is especially apparent for ResyncPeriod which had a few different implementations.

This does add the AllowCrossNamespaceImport to GrafanaNotificationPolicies, but it is not handled in the Reconciliation loop as of now.

It is recommended to review this one commit at a time.
Individual commits may not compile except for the final one.

[theSuess]

This looks good to me! Thanks for splitting this out. Would appreciate an additonal review just to be safe since this touches basically all resources