Add git OAuth authorization to the DevSpaces for cloning private repos

The user story can look this way:

• A user has a predefined cluster with git OAuth settings:
  https://www.eclipse.org/che/docs/stable/administration-guide/oauth-for-github-gitlab-or-bitbucket/
• The user creates for example empty DevSpace from the Dashboard sample and got the environment
  After this, he decided to set up an environment and clone the project from the private repo.
• The user clicks on F1 type clone -> enter private git URL in the field. After this, he should be redirected to the git OAuth page, pass the authorization procedure and the project should be cloned