feat(CRD): add extra validation + correct EC key validation method + add tests to CRD (Work In Progress)

[SequeI]

Summary

• Added extra validation to the CRD + improved documentation on configuration options
• Added tests for the CRD
• Fixed incorrect validation method, private key is not used to verify a signature, this could make the user confused so it has been changed
• Added a linter exclusion due to long x-k8s-validate ruleset
• Added a changelog file, seems like we will need it at this point (separate PR once more items get merged and I will do it all at once)
• Only the first validation method found gets used, so I locked the config to only one choice for the user as to not confuse them

Closes #20

Release Note

Documentation