[RFE] Document design of telco-gitops

[williamcaban]

There is are design considerations (like labeling scheme, mono-repo vs multi-repo, the type and privileges of ArgoCD instances, etc), that are built into the design of the repo but no public information on them is available. This RFE is for:

• How to use telco-gitops repo on various configurations for RAN & Core deployments (Combined, CU pool, DU pool, SNO DU, Core, etc)
• Include documentation of labeling scheme and how to extend it
• Include documentation ArgoCD instances and privileges
• Include documentation of service accounts and roles
• Include documentation on options for mgmt clusters

Use public reference from clusters by @williamcaban and @novacain1