docs: Add mkdocs-bibtex

[cwhite911]

We have the option to add the mkdocs-bibtex plugin to manage citations through out the documentation.

It would allow us to have a root bib file so that we can reference papers inline using the following format shown in an example from r.sim.water.

[@mitas_distributed_1998-1] Add's a footnote

"The numerical solution is based on the concept of duality between the field and particle representation of the modeled quantity. Green's function Monte Carlo method, used to solve the equation, provides robustness necessary for spatially variable conditions and high resolutions [@mitas_distributed_1998-1]."

This adds an auto generated citation at the end of the page

[wenzeslaus]

As I said earlier, this is out of scope for the switch to the new documentation. It does not bring any immediate advantage when only enabled, and applying to the existing pages is a large amount of work with limited benefits to the users of the tool. I'm also reluctant to enable every interesting plugin of mkdocs. More plugins, more dependencies. This one also seems like it would make things more complex with all the bibtex stuff, so we will have to be really sure before we purse this. I'm not voting no now and forever, and I see a value in managed, machine readable references, but we should not do this now.