Add values.schema.json

[theboringstuff]

Problem

It is required to introduce values.schema.json for the chart

Solution

• Added values.schema.json
  • Did not add description for the fields, since it would introduce duplication
  • Allowed additional properties to keep backward compatibility
  • Schema is detailed for SM-owned parameters, for others it is generic objects/arrays/etc
• Added missing labels required by release window

Test Cases

1. Make sure SiteManager deploys OK with both AppDeployer/ArgoCD
2. Make sure SiteManager schema validation fails if some incorrect types are specified

Example incorrect values:

createClusterAdminEntities: 123

Expected error:

$ helm template charts/site-manager/ -f env~/values.yaml 
Error: values don't meet the specifications of the schema(s) in the following chart(s):
site-manager:
- at '/createClusterAdminEntities': 'anyOf' failed
  - at '/createClusterAdminEntities': got number, want boolean
  - at '/createClusterAdminEntities': got number, want string