WIP: implement multi-namespace support

[hubeadmin]

Description

carrying over work from @d-kuro

To run:
Follow classic install procedure through make, i.e make install etc.

oc apply -f deploy/examples/multinamespace

make run GRAFANA_NAMESPACES="main-grafana,extra-grafana" DASHBOARD_NAMESPACES="" WATCH_NAMESPACE="main-grafana,extra-grafana" OPERATOR_NAMESPACE="main-grafana" <- this is getting overly complex

GRAFANA_NAMESPACES: the namespaces in which the operator can expect a Grafana instance
DASHBOARD_NAMESPACES: the namespaces from which the operator should grab dashboards
WATCH_NAMESPACE: I think this is pretty similar to GRAFANA_NAMESPACES in logic, I'll need to take a look into it
OPERATOR_NAMESPACE: the "host" namespace from which the operator pod should be run

Relevant issues/tickets

#174

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

[hubeadmin]

Please don't review it yet, this is a very dirty rebase of the current work onto the master branch.

[bakito]

I'm really looking into using this feature.
Currently I'm stuck with this operator, because I don't want to maintain multiple instances of the same operator in one cluster.

[addreas]

@bakito if you are feeling adventurous you might be interested in this: addreas@19d6ad0. It's definitely smaller in scope than this PR, but together with the --scan-all argument its been enough for my use (single grafana instance, watching all namespaces).

[bakito]

@addreas thank you very much for the hint. For my use-case I would need multiple instances of grafana in multiple namespaces.

[hubeadmin]

@bakito Thanks Marc, I've also replied to your email, I'm working on this currently! Thanks for showing your interest!

[bakito]

@HubertStefanski yes, I saw it. Thank you very much for your reply.
If you have a version ready to test, feel free to contact me.

[github-actions]

This PR hasn't been updated for a while, marking as stale

[bakito]

@HubertStefanski are you still working on this?