- Fix mis-used dependencies. Add the roughly proposed 'extends' model
for notebook renderers. Keep it out of contribution schema for now
until we can work it more.
- Made new loading work with JS modules.
- Consolidated the 'old style' code in the renderer so that we can just
delete it when the time comes.
- Removed duplicated code and sharp edges from the 'queue' mechaism.
* Better notebook markup renderer api
For #121256
- Use js modules for notebook output renderers
- Rename apis from `markdown` to `markup`
- Use imports and exports for apis instead of globals for apis
- Use esbuild instead of webpack so we can emit js modules
- Clearly split top level markup renderes from renderers that extend other renderers
* Use constant instead of comment for replacement
