Integrate mdxeditor

[petyosi]

Adds mdxeditor as an option for the rich text editor in the campaigns.

Closes #1503.

Motivation and context

MDXEditor works with Markdown, which drives the following improvements:

• Easier, editor-independent content storage
• Content can be SSR, driving better SEO
• Support for image paste, drag and drop
• Future integration with tables
• Preserve formatting when copy/paste from google docs

Screenshots:

Affects the campaigns administrative interface UI.

Testing

• TODO

Steps to test

Affected urls

• /admin/campaigns/edit/guid
• TODO

Environment

New or updated dependencies:

• MDXEditor (new)
• Bumps TypeScript to v5. TS5 reads the exports field from package.json, which means that only the editor parts used by the site will be included in the bundle
• Added some resolution rules, so that only one @types/react package is used (resolves errors with type-check)

[github-actions]

✅ Tests will run for this PR. Once they succeed it can be merged.

[petyosi]

Note: PR is to be squashed into a single commit, no useful semantics to be preserved.

[petyosi]

@igoychev - updated the package to prevent dialogs from submitting the entire form, check it out.

[igoychev]

Great to have the brand new editor! Thank you for the contribution and the well thought backward compatibility!