Shut down eregs application #855

The eregs application is no longer needed as the regulations search has been replaced by the eCFR API and the regulation links replaced with eCFR regulation links.

Technical steps:

• Shut down dev eregs application and check to make sure global legal search still returns all regulations: https://dev.fec.gov/legal-resources/
• Shut down stage eregs application and check to make sure global legal search still returns all regulations: https://stage.fec.gov/legal-resources/
• Shut down prod eregs application and check to make sure global legal search still returns all regulations: https://www.fec.gov/legal-resources/

Completion criteria:

• eregs app is shut down and removed in all 3 environments [prod, stage, dev]
• Create follow-up ticket to deprecate regulations openFEC API endpoint. Also remove from pingdom and statuspage.