Staging-50

What's Changed

• ISSUE #1500: Add "Check Availability" functionality for alternative domains by @erinysong in #1672
• Ticket #1643 - Remove stale form errors on the check availablity page by @zandercymatics in #1650
• ISSUE 1500: get-gov.js clean up by @therealslimhsiehdy in #1714
• Typo: assoicated to associated by @rachidatecs in #1720
• (On getgov-za) Ticket #1484: Domain manager delete by @zandercymatics in #1633
• Move the start and end date assignments inside check for elements by @rachidatecs in #1721
• Issue #1539: python test can be run in parallel threads in pipeline by @dave-kennedy-ecs in #1716

Full Changelog: staging-49...staging-50