Postman and Stub updates for testing ProvMns Error handling

Postman and Stub updates for testing ProvMns Error handling

- Aligned PolicyExecutor Stub simulations with DMI Stub
- Add Simulation for Policy Denial in Stub PE Controller
- Postman updates: Data (ProvMnS) folder, including:
  - get, put, del success scenarios
  - get, put, del error and deny scenarios
NOTE Enable Policy Executor (env variable) to test/demo deny scenarios!
- Also contains fix for double slash (will disappear once separate for commit for that is merged)
TODO
- PostMan Patch scenarios will be done in separate commit by Sean as it requires DMI Stub update too

Issue-ID: CPS-2707
Change-Id: I97f801e3de73062acaf0b6cf122be6e0a104974e
Signed-off-by: ToineSiebelink <toine.siebelink@est.tech>