Specreduce tutorial collection

[hpparvi]

This issue tracks the progress of the specreduce tutorial collection.

I (@hpparvi) am writing a collection of spectroscopy tutorials covering the functionality offered by specreduce. These are best collected into a book, preferably built with the Jupyter Book 2 framework. I've already drafted tutorials covering most of the functionality, but they need to be homogenised, and the coverage of some features could use improvement.

As a first step, and as discussed with @ceb8, it'd be great to have a repo set up with a working book template that I can start filling in.

This work will cover Issues #439, #630, #631, and #632, all of which can be assigned to me.

[ceb8]

Here is your repo: https://github.com/astropy-learn/tutorial--specreduce/tree/main/.github/workflows

And here is the Learn Dev guide, which has some useful information for submittig a set of tutorials that will be a book: https://github.com/astropy-learn/dev-guide

[hpparvi]

Thanks!