[NEW FEATURES] WeBWorK local PG processing

[Alex Jordan]

If you use WeBWorK in your PreTeXt project, you can now generate the static representations using a local copy of the pg repository (as opposed to a far away webwork2 server). This phase of processing will be significantly faster. Results will vary but we have seen projects take about 30% as long for the static representations build.

For how to set things up so you can do this, see:

https://pretextbook.org/doc/guide/html/webwork-local-pg-static-processing.html

There will be a one-time cost of installing pg and its dependencies. Those instructions could be improved, notably with a list of Redhat packages that would provide the needed perl modules. Please report or open a pull request if you find improvements to those instructions.