Issue title: Add option to save already input form (username/password)
 Issue body: Add option to save already input form (username/password),
When i finish to type username/password, let us save already input form.
We do not want to click the login, and want to save input before click login.

 Comments: 
 Comment 0: I like this as a potential solution, or partial solution, to #1620. Let's keep discussion to that thread to avoid duplication.
{'source': 'GithubIssues', 'repo_name_with_owner': 'bitwarden/browser', 'issue_id': 816078637, 'repo_stars': 4026.0}