Eliminating underscore

[ocket8888]

What does this PR (Pull Request) do?

• This PR is not related to any Issue

Removes UnderscoreJS (_.js) from the Traffic Portal dependencies and codebase.

Which Traffic Control components are affected by this PR?

• Traffic Portal

What is the best way to verify this PR?

Run the existing end-to-end TP tests, but also start a TP instance and pay close attention to any errors coming from the jQuery "data tables" and the charts on the dashboard. I think those are using lodash/defining their own variables named _, but the problem could just not be manifesting for me for some reason.

The following criteria are ALL met by this PR

• Existing tests should be sufficient
• Documentation of managed dependencies is not necessary
• An update to CHANGELOG.md is not necessary
• This PR includes any and all required license headers
• This PR does not include a database migration
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY

[mitchell852]

this is good (it's always good to remove a dependency imo) but it's highly intrusive and dangerous as the reality is that the TP end-to-end tests probably don't cover many of these "states" (not sure however). Bottom line: this is going to require a good deal of testing which is fine. Just wanted to point that out if someone (besides me) ends up reviewing/merging this.