customized registry namespace and MacOS support

1. User will create a human-readable namespace for their own account at first time.
2. User can remove the specific image away from the private registry on webpage.
3. MacOS support.
4. Fixed setup failure on some fedora version
5. Frontend improvement and bug fix
6. Added youtube link about Introduction of Crane
7. closed issues : #536 #527 #587 #535 #453 #546 #524 #452 #532 #429 #582