Updates Docusaurus to 3.5

[mhkuu]

Fixes #316

Summary

This PR updates Docusaurus to the latest version (3.5). This PR addresses all required changes to make the migration.

Relevant technical choices

The individual commits show how the updating took place:

1. 7c5ae4c updates the dependencies as per https://docusaurus.io/docs/migration/v3#upgrading-dependencies
2. a4e3a71 fixes some Markdown as per https://docusaurus.io/docs/migration/v3#using-the-mdx-checker-cli
3. 2f7c047 transforms the configuration file, with the most pressing change being the way we import themes, see https://docusaurus.io/docs/migration/v3#prism-react-renderer-v20
4. 643e56d fixes the MDX loader for the changelog plugin, see fix: remove useless js-loader in front of mdx-loader facebook/docusaurus#8972 for context.
5. 8b4586a updates the imports, as some stuff has moved from @docusaurus/theme-common/internal to plugin-content-blog/client or plugin-content-docs/client.
6. b8b89d9 moves plugin-content-blog to an actual dependency instead of a development dependency.

Test instructions

This PR can be acceptance tested by following these steps:

1. Run docusaurus clear and delete node_modules to prevent any caches.
2. Run yarn to install all dependencies.
3. Run npx docusaurus-mdx-checker and confirm all files are compiled successfully.
4. Run yarn start and confirm the developer docs are locally built and served successfully.
5. Run yarn build and yarn serve to confirm the developer docs can also be successfully built for production.
6. Do a few smoke tests to confirm everything works as before.

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