Create JAX Advanced Tutorials (section, move/create docs)

[8bitmp3]

@jakevdp

[jakevdp]

Several of these sections are duplicative of existing docs (e.g. docs/external-callbacks.md and docs/notebooks/external_callbacks.md.

More work is necessary to de-duplicate these, update indices, and re-direct old URLs to the new locations. See #21064 for an example of how we did this in the past

Also, rather than creating new files, we should move the old files out of docs/_tutorials to their new location, in order to preserve change history.

[jakevdp]

Errors are due to the change noted below; also it looks like there are two remaining uses of the understanding-jaxprs reference that need to be updated, one in glossary.rst and one in jit-compilation.md.

[8bitmp3]

@jakevdp PTAL

[jakevdp]

As we discussed, the structure of the left-nav dropdown is still not exactly how we'd like it, but we can land and iterate. Thanks for working on this!