Add read-only mode in the SDC library

[jingtang10]

IMPORTANT: All PRs must be linked to an issue (except for extremely trivial and straightforward changes).

Fixes #1704

Description
Add read-only mode in the SDC library.

• introduce a new argument to the questionnaire fragment QuestionnaireFragment.EXTRA_READ_ONLY
• setting this argument to true while launching the questionnaire fragent will set the questionnaire in read-only mode
• read-only mode will look like review mode but without the option to edit the answers

Alternative(s) considered
NA

Type
Feature

Screenshots (if applicable)
NA

Checklist

• I have read and acknowledged the Code of conduct.
• I have read the Contributing page.
• I have signed the Google Individual CLA, or I am covered by my company's Corporate CLA.
• I have discussed my proposed solution with code owners in the linked issue(s) and we have agreed upon the general approach.
• I have run ./gradlew spotlessApply and ./gradlew spotlessCheck to check my code follows the style guide of this project.
• I have run ./gradlew check and ./gradlew connectedCheck to test my changes locally.
• I have built and run the demo app(s) to verify my change fixes the issue and/or does not break the demo app(s).

[omarismail94]

Nice, clean change Jing! Left a few minor comments

[jingtang10]

thanks omar can you take another look?

[jingtang10]

thx omar!