Add Technology Categories report, linking tech categories to software titles

Very similar to the [business capabilities report](https://stage.ea.gsa.gov/#/capabilities) where it shows the business systems associated with each capability, we're going to need to add a technical reference model (TRM) report which ties IT standards (software titles) to technology categories. We have the data to do that already available.

- [x] Create an API for the TRM itself. Currently, we have the api/it_standards/categories API, but it only returns the Id and Keyname. We'd probably want this to be its own dedicated js files in the API folder rather than adding it to the it-standards model/route/controller, similar to how capabilities is separate.
- [x] Create an API for the TRM to IT standard (software) pairing.
- [ ] Document the API
- [x] Add a report view for the TRM
- [x] Add a detail view for the TRM which lists a table of associated IT standards
- [x] Add the report to the global search results
- [x] Add the report view link in the left sidenav as "Technology Categories" under the "Technologies" heading
- [x] Document the front end data fields of the new report in the Data Dictionary
- [x] Create Technology Categories chart (i.e. the dendrogram, similar to business capabilities and org chart)
- [x] Add table to the IT standards detail page for the TRM related to that IT standard (clickable to the TRM detail)
- [x] Remove "Category" from the IT standards report and detail pages
- [x] Add helper text to the Technology Category List (report view and detail page)
- [x] For consistency the title that appears on the model and list views should be named the same title as appears on the left sidenav. Please change the name of the [Tech Category List](https://stage.ea.gsa.gov/#/tech_categories) from "Technology Reference Model" to "Technology Category List". Please change the name of the [Tech Category Model](https://stage.ea.gsa.gov/#/tech_categories_model) to "Technology Category Model".