* Clean up ref name rules
Clean up checks on reference names to better conform to the guideline
here: https://git-scm.com/docs/git-check-ref-format
This fixes half of #6321
* Update branch create integration test
According to: https://git-scm.com/docs/git-check-ref-format
And: git check-ref-format "master/feature=test1"
This is a valid branch name and we should not be testing for it to fail.
* Add correct git branch name validation
* Change git refname validation error constant name
* Implement URL validation based on GoLang url.Parse method
* Backward compatibility with older Go compiler
* Add git reference name validation unit tests
* Remove unused variable in unit test
* Implement URL validation based on GoLang url.Parse method
* Backward compatibility with older Go compiler
* Add url validation unit tests
