Add CHAPI support for Share Credential Request workflow - Get Requests

[bmuramatsu]

Add CHAPI support for Share Credential Request workflow.

Note: This issue is for presenting a credential from LCW (hence the Share Credential Request) part.
For support for issuing a VC into LCW, see issue #504

[bmuramatsu]

Works in Android, Build 52

[kayaelle]

@dmitrizagidulin - please add instructions for Atomic Jolt team

[alexfigtree]

From @dmitrizagidulin:

CHAPI allows two workflows:
The store() workflow - getting a VC from an issuer INTO LCW. That part we have working (although the UX is awkward).
The get() workflow -- getting a VC FROM LCW to some webpage. (Or to some external API endpoint).

This ticket is about that second get() workflow.

At verifiers/Relying Party's web page, user is asked for a VC. User then clicks a button like 'Present Credential', and now the web page has to communicate with LCW, and get a credential out of there (with the user's permission)

How to test this second workflow (to see if we support it):

1. Go through wallet setup again. (Uninstall / reinstall app, or go to Settings > Reset Wallet, and relaunch the app).
   This time, don't skip the Register step. Click on Register Wallet. You'll be taken to the register web page. click Register there. Then switch back to the wallet

2. Now lets get a VC into the wallet (from flow 1).

3. Go to https://vcplayground.org/issuer (in your mobile browser)

4. In the upper right of the playground issuer webpage, click the Settings gear, select VC-API to any Wallet

5. Click Issue Verifiable Credential blue button.

6. Click Skip DID Authentication

7. this should open LCW and present you with the VC, and an Accept/Decline screen. Accept credential, click Done on the wallet.

8. And now it's time to present that VC you just got into the wallet, at a verifier.

9. Now go to https://vcplayground.org/verifier (also mobile browser)

10. Gear in the upper right, click VC-API to any Wallet. Select 2nd icon 'Open Badge'.

11. Click Request Verifiable Presentation

12. This should open up LCW, and present a 'Share VC' confirmation screen, if all is working

[alexfigtree]

Issue blocked on #547.

[dmitrizagidulin]

Ok, #547 has been fixed, but now blocked on issue #598

[alexfigtree]

Both #547 and #598 have been closed, can now close this issue.