[CX] Remove the use of Static Node level singletons

Currently, some node level objects (mainly application context on the cluster controller) are static singleton. This is problematic in many cases:

1. Other nodes (NCs) are accessing such objects even though they shouldn't.
2. Testing is different for Integration tests and Runtime tests.
3. No access control to such objects (anyone can access them)
4. Will hinder scaling of compilation nodes.