Add builder pattern plugin system

[OR13]

Summary of Changes

These changes are isolated to the "example implementation", however they likely motivate some minor changes to the spec.

The test vectors generated from these tests, should be added to the spec.

The issues that were resolved related to spec data models, need to be closed, after the spec text is updated.

Checklist

• [x] Use builder pattern to dynamically build wallet with typed interface support
• [x] Implement DID Method Key Plugin
• [x] Add "generatedFrom"
• [x] centralize test vectors in node module
• [x] move vc interface to plugin
• [x] move edv interface to plugin
• [x] Reduce bundle size by moving crypto to plugins
• [x] fix https://github.com/w3c-ccg/universal-wallet-interop-spec/issues/12
• [x] fix https://github.com/w3c-ccg/universal-wallet-interop-spec/issues/2
• [x] update web demo