Persist everything to disk so a trained instance can be loaded

[ClimbsRocks]

The goal is to train machineJS, serialize it and all of it's components to JSON/.pkl, then be able to load in all the trained components again on a different machine.

[ClimbsRocks]

Some things we'll have to save:

List of known steps required to write everything to disk and load up a fully-trained ppc instance at some future point:

data-formatter: min-max-scalers (one per column)
data-formatter: imputing missing values
what counts as a missing value
what is it replaced by?
this is just some code I picked off the internet, so we'll have to save and load this module by hand
it shouldn't be hard though- just save one overall list of what is considered a missing value
save an array, with one value for each column, that is the replacement value for that column.
data-formatter:
minimum date in date column