Issue 49858 - Add backup/restore and import/export functionality to WebUI/CLI
    
    Description: dsconf tool now has:
    'dsconf localhost backup create' and 'dsconf localhost backup restore';
    'dsconf localhost backend import' and 'dsconf localhost backend export'.
    Add basic tests for the CLI part
    Add JS logic for online backup/restore.
    Add more HTML and JS for online import/export functionality.
    Fix CSS alignment issues. Fix validity checks in CLI.
    
    https://pagure.io/389-ds-base/issue/49858
    
    Reviewed by: mreynolds, wibrown, mhonek (Thanks!)