Release v0.5.1

[mazin-s]

What this PR does / why we need it:
This PR bumps the operator version from v0.5.0 to v0.5.1.

Helm Before:

Helm After:

How Has This Been Tested?:
make run-automation-provisioning
pg-provisioning-si_test.txt (successful)
mysql-provisioning-si_test (successful)
mongo-provisioning-si_test (The client VM for this operation has been powered off)
mssql-provisioning-si_test:

make run-automation-cloning
mssql-cloning-si_test.txt

make test-coverage

Release note:

1. Bumped up go version in go.mod and workflows from 1.20 to 1.21.7.
2. Bumped up kube-rbac-proxy version from v0.15.0 to v0.16.0.
3. Removed samples folder reference which was located in config/manifests/kustomization.
4. Fixed static lint errors
5. Increased unit test coverage to 78%.
6. Add a new makefile target to give coverage numbers
7. Introduced an interface for the rest client - NDBClientHTTPInterface to mock the responses from NDB instead of spinning up a new http server for every test. 
8. Added E2E additional logging for setting up log environment failure case.

[manavrajvanshi]

I feel that the release notes and the changes are not consistent, nonetheless everything LGTM!