Demo app for activity flow

[aditya-07]

Fixes #2700

Description

1. Demo app to show case activity flow api.
2. Landing page has a Patient card, a carousel of cards (phase card) related to each phase of activity flow and an overflow menu to select a particular activity to run.
3. Each phase card has a start button to activate the phase . The start button is enable only for the phase that is logically the next phase in the activity flow cycle.
4. On pressing the start button, the request/event for the particular phase are generated either from the CarePlan (Proposal Phase) or the previous phase requests (Plan/Order/Perform phases).
5. All the requests and persisted in the engine.
6. If you want to run the same flow again, click restart flow, which removes all of the resources related to the selected activity flow from the engine and moves the flow back to start proposal phase.

Alternative(s) considered
NO

Type
Choose one: Feature

Screenshots (if applicable)

activity_flow_demo_app.mp4

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).