Add "investigations" and "other reports" categories to OIG reports page

[dorothyyeager]

Summary

What we are after:
The OIG has requested that we add an "investigations" category to their reports page.

In addition, we will want to add the recently created "Other reports and plans" category to the document page template used by IG.

Page URL: https://www.fec.gov/about/reports-about-fec/oig-reports/

Action items

We’ll need to update the OIG reports categories to include Investigations in the list of categories that can be chosen, and as an option in the Wagtail template page too

Completion criteria

• Investigations is added as a category to https://www.fec.gov/about/reports-about-fec/oig-reports/
• Other reports and plans is added as a category to https://www.fec.gov/about/reports-about-fec/oig-reports/
• Wagtail document page template is updated
• Document page for Investigative Summary 12INV00037 Allegations of Bias Against FEC Personnel Reviewing 58th Presidential Inaugural Committee Reports is updated to move into the "investigations" category
• Confirm with OIG whether there are other reports/documents that may need to move

[JonellaCulmer]

Do we know if there are existing reports that will need to move into this new category?

[dorothyyeager]

@JonellaCulmer The one posted last week (see 4th item in completion criteria).