Expand Config Apply Integration Tests

[aphralG]

Proposed changes

• Added tests:
  • Add, Update & Delete File Config Apply Using Mock (New sub directory)
  • Add, Update & Delete File on Data Plane (New sub directory)
  • Add Check for Manifest file for all Config Apply Tests
  • Fix Mock Management Plane to allowing Adding of new file

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• I have run make install-tools and have attached any dependency changes to this pull request
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• If applicable, I have updated any relevant documentation (README.md)
• If applicable, I have tested my cross-platform changes on Ubuntu 22, Redhat 8, SUSE 15 and FreeBSD 13

[craigell]

Don't think we need to add test numbers in test names e.g. TestConfigApply_Test4_TestInvalidConfig. Names should be enough TestConfigApply_InvalidConfig,

[aphralG]

Discussed in office - Test Suites run in alphabetical order so to get the tests to run in specific order need to be numbered.