[Feat] Save/load models to/from file

[quantum9Innovation]

Is your feature request related to a problem? Please describe.
There is no problem directly related to this feature request, though it would solve issues relating to model reproduciblity, which will prove especially useful in research.

Describe the solution you'd like
Two functions, each of which compile an epispot model object into a file (JSON would probably be best, though any object-oriented file type like YAML/TOML could theoretically work). For certain abstract elements related to the models, (e.g. parameters defined as functions) values could be linked to names or special codes which could be interpreted later with the help of a dictionary. With this dictionary, the reader function would be able to read from the file and recreate the model in its original form, solving the problem of reproducibility and drastically lowering the file size required to do so.

Describe alternatives you've considered
There are, of course, multiple alternatives to solving the reproducibility issue, outlined below:

(1) Copying code: While this works, it's inefficient, occasionally hard to read (as it can be clouded with unnecessary functions and scripts), and involves large file sizes for a problem that can be solved more cleanly by other means.

(2) Saving model outputs: This is perhaps the most obvious solution, but it prevents researchers from actually inspecting the models producing the results and only shows part of the larger picture.

(3) Compiling the model to lower-level code ⁉️: Very efficient, but almost certainly unreadable. Why would we ever want to do this??

Additional context
It would be nice to ship this with epispot v3b, but the current situation makes that look unlikely. Regardless, @Quantalabs will head development until this enters nightly (or, if we're lucky, beta) testing.

[Quantalabs]

/available (LGTM!)

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