Run webhooks as part of the main manager

[vincepri]

User Story

Given that #3042 for v1alpha4 requires single controllers managing all namespaces, we should move the webhooks back in the main manager and run them behind RBAC in case we'll need a client in the future.

Anything else you would like to add:

@fabriziopandini @wfernandes Clusterctl upgrade and operator needs to perform this migration as part of the upgrade path from v1alpha3.

/kind feature
/milestone v0.4.0

[fabriziopandini]

That's a huge simplification, yay!

[wfernandes]

I'll make a note of it somewhere in the CAEP. Thanks. And yes, definitely a huge simplification!

[wfernandes]

Just adding for future reference. This issue is referenced in the management cluster operator caep under the Upgrade from v1alpha3 management cluster to v1alpha4 cluster section.

[fabriziopandini]

I'm starting to work on this issue, with the goal to start clarifying impacts on clusterctl init and clusterctl upgrades
/assign
/lifecycle active