Add custom style attributes

[FikriMilano]

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

Fixes #501 (GSOC Project)

Description
Create default style for the views in Data Capture Library then override it in SDC Gallery and change it with our own custom style.

Alternative(s) considered
N.A

Type
Choose one: Feature

Checklist

• I have read and acknowledged the Code of conduct
• I have read How to Contribute
• I have read the Developer's guide
• 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 reference app(s) to verify my change fixes the issue and/or does not break the reference app(s)

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[google-cla]

All (the pull request submitter and all commit authors) CLAs are signed, but one or more commits were authored or co-authored by someone other than the pull request submitter.

We need to confirm that all authors are ok with their commits being contributed to this project. Please have them confirm that by leaving a comment that contains only @googlebot I consent. in this pull request.

Note to project maintainer: There may be cases where the author cannot leave a comment, or the comment is not properly detected as consent. In those cases, you can manually confirm consent of the commit author(s), and set the cla label to yes (if enabled on your project).

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[santosh-pingle]

It looks ok to me, just left few comments.
Thanks!

[FikriMilano]

@santosh-pingle could you review this again? thanks

[santosh-pingle]

LGTM

[qiarie]

@FikriMilano Please merge latest changes in master

[FikriMilano]

Could someone give me some insight on how to test this? because a huge part of the changes are from xml

[jingtang10]

1. I was testing this and couldn't get thing to work... and then realised that in values-night/themes.xml the theme override isn't set.... can you please add this to the that file similar to value/themes.xml:

        <!-- Customize theme for questionnaires in this application. -->
        <item name="questionnaire_theme">@style/Theme.MyQuestionnaire</item>

2. Please rename the PR name to something like Add custom style attributes
3. I think the most critical part of this PR is that you're adding the custom style attributes, I don't feel it's necessarily that useful to provide an example for each one in the datacapturegallary app - I think you can simplify that file, having one or two examples is enough, especially no need to override the tint effect for radio buttons.

[FikriMilano]

Alright, thanks for the feedback