[v3.4] 494 import equipment

resolves #494 as requested by CSSI; this will need to be merged into `master` as well. I'm going to clean up the branch and remove the testing since it was barely set up; the import was working fine so in the interest of getting the feature implemented I think we should skip testing for now. Additionally, we probably want to refactor all of the import code at some point as well. I'll also verify that all of the changes to the category, equipment model, and equipment object models have been taken into account.