Introduce script and action step to build documentation

[vorburger]

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

Related to #2232

Description

This PR contains x2 Commit. You may want to review and merge #2459 separately, first? Or both together here - your call.

I'm intentionally raising small changes; this alone doesn't "do" all that much, yet; my plan is to gradually build upon this.

Type Choose one: Builds

Checklist

• [X] I have read and acknowledged the Code of conduct.
• [X] I have read the Contributing page.
• [X] I have signed the Google Individual CLA, or I am covered by my company's Corporate CLA.
• [X] 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).

[vorburger]

@santosh-pingle or @jingtang10 do you want me to "self merge" this (and future related) changes, or do you want to review?

[jingtang10]

@santosh-pingle or @jingtang10 do you want me to "self merge" this (and future related) changes, or do you want to review?

prefer to review :)

[vorburger]

Kokoro: Build and Device Tests — Kokoro build failed. Check logs for details.

@jingtang10 looks like this ^^^ is due to:

┌─────────┬──────────────────────┬────────────────────────────┬───────────────────────────────────┬───────────────────────────────────┬────────────────────────────────┐
│ OUTCOME │      MATRIX ID       │          APP NAME          │          TEST FILE NAME           │          TEST AXIS VALUE          │          TEST DETAILS          │
├─────────┼──────────────────────┼────────────────────────────┼───────────────────────────────────┼───────────────────────────────────┼────────────────────────────────┤
│ success │ matrix-22nv06xa30fdw │ demo-debug-androidTest.apk │ datacapture-debug-androidTest.apk │ Nexus6P-24-en_US-portrait         │ 91 test cases passed           │
│ failure │ matrix-22nv06xa30fdw │ demo-debug-androidTest.apk │ datacapture-debug-androidTest.apk │ MediumPhone.arm-33-en_US-portrait │ 1 test cases failed, 92 passed │
└─────────┴──────────────────────┴────────────────────────────┴───────────────────────────────────┴───────────────────────────────────┴────────────────────────────────┘

which is very very likely completely unrelated to this PR? How do you want to handle this? Do you want to just merge this as-is anyway?