feat(sdk): Support for the OAuth Discoverable Client ID Scheme

[DRK3]

• Support for the OAuth Discoverable Client ID Scheme described in https://mattrglobal.github.io/draft-looker-oauth-client-id-scheme/draft-looker-oauth-client-id-scheme.html.
• Added documentation for how to use this scheme with Wallet-SDK.
• Updated documentation for the other methods of getting/providing a client ID.
• Eliminated some code duplication by doing some refactoring.

[sonarcloud[bot]]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
3.5% Duplication

[codecov-commenter]

Codecov Report

Patch coverage: 96.96% and project coverage change: +0.10% :tada:

Comparison is base (fe4a68a) 89.69% compared to head (5741113) 89.79%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #530 +/- ## ========================================== + Coverage 89.69% 89.79% +0.10% ========================================== Files 97 98 +1 Lines 3745 3745 ========================================== + Hits 3359 3363 +4 + Misses 257 255 -2 + Partials 129 127 -2 ``` | [Files Changed](https://app.codecov.io/gh/trustbloc/wallet-sdk/pull/530?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=trustbloc) | Coverage Δ | | |---|---|---| | [cmd/wallet-sdk-gomobile/openid4ci/interaction.go](https://app.codecov.io/gh/trustbloc/wallet-sdk/pull/530?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=trustbloc#diff-Y21kL3dhbGxldC1zZGstZ29tb2JpbGUvb3BlbmlkNGNpL2ludGVyYWN0aW9uLmdv) | `95.91% <95.91%> (ø)` | | | [...k-gomobile/openid4ci/createauthorizationurlopts.go](https://app.codecov.io/gh/trustbloc/wallet-sdk/pull/530?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=trustbloc#diff-Y21kL3dhbGxldC1zZGstZ29tb2JpbGUvb3BlbmlkNGNpL2NyZWF0ZWF1dGhvcml6YXRpb251cmxvcHRzLmdv) | `72.72% <100.00%> (+10.22%)` | :arrow_up: | | [...k-gomobile/openid4ci/issuerinitiatedinteraction.go](https://app.codecov.io/gh/trustbloc/wallet-sdk/pull/530?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=trustbloc#diff-Y21kL3dhbGxldC1zZGstZ29tb2JpbGUvb3BlbmlkNGNpL2lzc3VlcmluaXRpYXRlZGludGVyYWN0aW9uLmdv) | `88.17% <100.00%> (-2.34%)` | :arrow_down: | | [...k-gomobile/openid4ci/walletinitiatedinteraction.go](https://app.codecov.io/gh/trustbloc/wallet-sdk/pull/530?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=trustbloc#diff-Y21kL3dhbGxldC1zZGstZ29tb2JpbGUvb3BlbmlkNGNpL3dhbGxldGluaXRpYXRlZGludGVyYWN0aW9uLmdv) | `75.40% <100.00%> (+0.74%)` | :arrow_up: | | [pkg/openid4ci/createauthorizationurlopts.go](https://app.codecov.io/gh/trustbloc/wallet-sdk/pull/530?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=trustbloc#diff-cGtnL29wZW5pZDRjaS9jcmVhdGVhdXRob3JpemF0aW9udXJsb3B0cy5nbw==) | `80.00% <100.00%> (+5.00%)` | :arrow_up: | | [pkg/openid4ci/interaction.go](https://app.codecov.io/gh/trustbloc/wallet-sdk/pull/530?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=trustbloc#diff-cGtnL29wZW5pZDRjaS9pbnRlcmFjdGlvbi5nbw==) | `86.99% <100.00%> (+0.12%)` | :arrow_up: | | [pkg/openid4ci/issuerinitiatedinteraction.go](https://app.codecov.io/gh/trustbloc/wallet-sdk/pull/530?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=trustbloc#diff-cGtnL29wZW5pZDRjaS9pc3N1ZXJpbml0aWF0ZWRpbnRlcmFjdGlvbi5nbw==) | `91.79% <100.00%> (ø)` | | | [pkg/openid4ci/walletinitiatedinteraction.go](https://app.codecov.io/gh/trustbloc/wallet-sdk/pull/530?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=trustbloc#diff-cGtnL29wZW5pZDRjaS93YWxsZXRpbml0aWF0ZWRpbnRlcmFjdGlvbi5nbw==) | `72.00% <100.00%> (ø)` | |

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