Clean up tutorial organization

[huddlej]

Consolidates introductory tutorials (Zika and TB) into this repository, removes references to the alternate Zika tutorial from the Augur repository, and provides more explanatory titles for each tutorial.

Moving the TB tutorial into this repository allows us to keep the Zika and TB content in the same place.

[eharkins]

Thanks John! I activated a RTD build for this here https://docs.nextstrain.org/en/dedupe-zika-docs/tutorials/index.html just to check it builded and looked as I expected from the diff - looks good, that build version can be deactivated (or maybe that happens automatically if you delete the branch after merging).

Just a reminder that https://github.com/nextstrain/augur/blob/master/docs/tutorials/tb_tutorial.md should be removed when you merge.

Meanwhile I suppose you can wait to remove https://github.com/nextstrain/augur/blob/master/docs/tutorials/zika_tutorial.md from augur until it is transformed into a snakemake oriented advanced tutorial / guide.

[eharkins]

I think a redirect might be necessary for zika. Otherwise, the merged (replacing latest for the branch name) version of this link will 404: https://docs.nextstrain.org/en/dedupe-zika-docs/tutorials/zika_tutorial.html (this 404s now and I believe that behavior will carry over when merged to master/latest).

Seems like we want to redirect https://docs.nextstrain.org/en/latest/tutorials/zika_tutorial.html to
https://docs.nextstrain.org/en/latest/tutorials/zika.html - even though in the future the zika_tutorial will become something else altogether (snakemake tutorial), i think this is the best place we can redirect it for now in the absence of that snakemake tutorial.

I think this can be implemented by configuring the following redirect at https://readthedocs.org/dashboard/nextstrain/redirects/:

Page Redirect
/tutorials/zika_tutorial.html -> https://docs.nextstrain.org/en/latest/tutorials/zika.html

You can configure this redirect before merging, and the behavior I would expect based on my experience with RTD redirects is that it will apply to the dedupe-zika-docs to fix the 404, but will not apply to latest until this PR is merged since the zika_tutorial path will still exist on that branch until this is merged. This is nice since it is a way to test redirects are working before removing a page.

[huddlej]

Thank you for checking this out, @eharkins! I added a redirect for /tutorials/zika_tutorial.html -> /tutorials/zika.html and it works as expected for https://docs.nextstrain.org/en/dedupe-zika-docs/tutorials/zika_tutorial.html.

I will follow this PR up with the separate one for the Zika + Snakemake tutorial we discussed (starting with the old zika_tutorial.md content initially).

[huddlej]

Merging this since the Zika tutorial in Augur no longer exists and new branches from current master break on the fetch_docs command when they try to pull that Zika tutorial. I created a new branch and a draft PR for refining this Snakemake-based Zika tutorial and the TB tutorial.