RBAC add possability to patch events

[NissesSenap]

Description

This way --scan-all don't have to add any custom clusterroles.
Solves #630

Relevant issues/tickets

#630

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• This change requires a documentation update
• I have added tests that prove my fix is effective or that my feature works
• I have added a test case that will be used to verify my changes
• Verified independently on a cluster by reviewer

Verification steps

• Update the deployment, to use --scan-all: https://github.com/grafana-operator/grafana-operator/blob/master/deploy/manifests/latest/deployment.yaml
• k apply -k deploy/manifests
• k apply -f deploy/examples/Grafana.yaml
• Add dashboards to a random namespace with the correct selectors.

You shouldn't see any errors.

[NissesSenap]

In v4 we have gone over to using cluster roles instead of roles to create access. This is much due to OLM will shift towards only using cluster wide operators.
It's also a premature preparation for multi-namespace support. If we add this patch I think we can remove https://github.com/grafana-operator/grafana-operator/tree/master/deploy/cluster_roles all together since all the needed access should be set.

This rule is probably needed for a single namespace as well and when we have done our testing we probably haven't updated our dashboards enough to find the issue.