See available git branches when creating a workspace in User Dashboard

[AObuchow]

Is your enhancement related to a problem? Please describe

The Che User Dashboard allows users to select a specific git branch that they want their CDE to be started from, however, this is a blank text box that requires the user to know the exact git branch name that they want to use.

If the user does not know the exact name of the branch they want (or they're afraid of making a typo), they have to manually check their git repo and copy/paste the name of the desired branch.

Describe the solution you'd like

It'd be nice if the User Dashboard was able to retrieve the list of branches that are available for the given git repository, and provide them to the user.
I'm not sure what the best UX for this would look like, but here are 2 ideas:

• An "autocomplete" text box, where the git branch matching what the user has typed (so far) will be written out in grey, and hitting the Tab key will accept the autocompletion.
• An "autocomplete" drop, where the user can select from a list of git branches, or type in the branch name and make use of autocomplete.

Describe alternatives you've considered

No response

Additional context

No response