[Feature]: Manage Namespaces via Monoskope

[christianhuening]

We discovered that for the feature to really work out all RBACs it has to know namespaces that exist in clusters. After a discussion we decided that namespaces should be something managed by m8 too.

AC:

• Namespaces manageable via monctl
  • Create server API
  • Implement Aggregate/Projection/Query
  • add/edit labels and annotations
• Tenant admins can create namespaces adhering to naming rules (prefixes) for their tenant
• System admins can create namespaces with any name
• Namespaces are connected to cluster(s) and a single tenant
• The git repo reconciler creates namespace yamls too
• The git repo reconciler creates rolebindings for tenant users in that namespace as needed for app oncall for example