Rich text viewer | Implementation of markdown parser

[vivinkrishna-ni]

Pull Request

🤨 Rationale

This PR includes the logic for parsing markdown input and rendering the rich text content into the viewer component.
Issue: #1288
AzDo User Story: Show the rich text content by parsing the markdown input

👩‍💻 Implementation

• Added prosemirror-markdown package for parsing markdown strings, and prosemirror-model package for DOM serializer to serialize the content and render the rich text content in the UI.
• Added markdownValue accessors to allow setting and retrieving the markdown value. When setting the markdown input string, the component performs operations to convert the markdown string into corresponding document fragments for loading it into the container of the viewer component.
• Enabled emphasis, list, and autolink from the markdown-it, which is internally used by prosemirror-markdown. This allows users to add bold, italics, numbered, and bulleted lists, as well as direct links in a CommonMark flavor. All other basic markdown formats are disabled.
• Added json() from the "@rollup/plugin-json" in the rollup.config.js because prosemirror-markdown and markdown-it internally use JSON files during the build process. Referred to this solution from the discussion here.
• Also, added nodePolyfills() from rollup-plugin-polyfill-node as the markdown-it requires punycode(code reference) but as mentioned in the punycode, the right way to use it is require('punycode/'). So use nodePolyfills() to rollup the bundle with the punycode properly imported in the all-components.bundle.js.

Spec update:

1. Latest comments desktop and mobile mockup links and updated a few GitHub permalinks.
2. Removed the fit-to-content attribute for the viewer component.
3. markdown accessor is changed to a property for the viewer component.

🧪 Testing

Added unit tests and manually tested and verified the changes.

✅ Checklist

• I have updated the project documentation to reflect my changes or determined no changes are needed.

[vikisekarNI]

I am approving this PR to unblock you next week as I will be out of office, otherwise would take another pass.

Pls go through the comments and address them as necessary.

[vivinkrishna-ni]

moved to thread: #1335 (comment)

[jattasNI]

Looking great! I just want to see how the remaining open threads resolve and then take one final look at the Chromatic diffs before approval.

[rajsite]

Approved assuming default normalization is re-enabled with test cases added

[jattasNI]

You're good to merge this PR this whenever you're ready! (No need to wait on the last reviewer)