additional documentation updates related to the fujilupe VACs

[moustakas]

There are a few outstanding tasks related to the release of the Fuji and Guadalupe VACs (the latest documentation is here):

• [ ] Add an acknowledgements page (both on using the code and the data / VACs).
• [ ] Write the algorithms documentation page.
• [ ] Independently test the code installation instructions, including the desihub dependencies.
• [ ] Register FastSpecFit with ASCL and add the bibcode entry to the README and documentation.
• [ ] Consider uploading to PyPi.

[moustakas]

Update the acknowledgements section https://github.com/desihub/desidatadocs/pull/3

[moustakas]

Done in #114.