NIAD-3132 Populate the "no disclosure to patient" label for Encounter

[martin-nhs]

What

1. I have refactored the previous implementation of handling confidentiality codes to utilising a service, this helps to create a more decoupled solution, now requiring us to simply place @Autowired on the ConfidentialityService.
2. Added "no disclosure to patient" support for Encounters.

Why

Please include details of the reasoning for these changes

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• I have performed a self-review of my code
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have updated the Changelog with details of my change in the UNRELEASED section if this change will affect end users
• A corresponding change has been made to the Mapping Documentation repository