Suggest the user to use bioAuth after the first successful sign-in - Closes #284

[reyraa]

What was the bug or feature?

Described in #284

How did I fix it?

• It'll suggest only the first time the user signs in.
• It'll bio-auth the users before letting them activate the bio-auth methods.
• If the user cancels any of the prompts at any stage, the bio-auth methods won't be activated and the user will be directly signed in.

Type of change

• Enhancement (a non-breaking change which adds functionality)

Note:
This PR doesn't implement the bioAuth dialog in Android since this will be addressed by #290 .

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[yasharAyari]

Thanks