Cluster Wide install mode

What

RHOAM team would like to extend 3scale operator functionalities to make it cluster scoped as well as namespace scoped. There is an epic in Managed API board that has a few tasks that were highlighted and will help the RHOAM team to move this feature forward.
Epic Link: https://issues.redhat.com/browse/MGDAPI-1595

Some of the areas that are going to have to be taken into consideration:
1. We also need the 3scale operator to be namespace scoped for backward compatibility, we need to ensure that customers that want to stay on namespace scoped 3scale operator can do so
2. We need to check how will the upgrade path look like ie from namespace scoped to cluster scoped

3. A testing plan must be agreed on between RHOAM and 3scale QE team

Reviews:

• Review whether having the operator in a different namespace than the CRs is a problem, for all CRDs: APIManager, APIManagerBackup, APIManagerRestore, the Capabilities CRDs... there might be some code that assumes that the namespace of the objects is the same namespace than the namespace of the operator. Changing to cluster scope would break that

• Review impact at permissions level: what changes regarding roles, clusterroles and what impact does it have when releasing it with OLM?

• Review what is the impact of doing a new release with the operator being cluster-role, taking into account existing users: existing users will have one or more 3scale operators (with namespace mode) in a single cluster, potentially with different 3scale versions installed. Maybe this ends up with needing talks to Product team

• Review impact on the upgrades code implementation. Now that the operator is cluster-scoped do upgrades code implementation still work? is the blast radius impact increased?

• Review impact on productization. Does it have an impact on the way we release? will our current tagging strategy, replaces/skipRange strategy still work?

• Are we going to support both namespaced and cluster scoped operator? what are the implications on each case?