Removes checks that are not useful

• Removes checks that are repetitive through our own monitoring system
• Removes checks that are here for performance monitoring
  • These will be kept safe using our blackbox monitoring
• Addresses: https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/5548

Manual Actions

• We have a number of checks that are paused and others that are deemed unnecessary, these will be manually removed:
  • http://about.gitlab.com - it's like repeated for some reason - paused
  • http://gitlab.org - paused
  • http://about.gitlab.com/ - paused
  • https://deps.sec.gitlab.com/api/ping - paused
  • https://forum.gitlab.com - paused
  • https://gitlab-examples.gitlab.io - paused
  • https://gitlab.com/ - again this one is just repeated several times for some reason - paused
  • https://gitlab.com/gitlab-com/gitlab-com-infrastructure/tree/master - paused
  • https://gitlab.com/gitlab-org/gitlab-ce/issues/1 - paused
  • alerts.gitlab.com
  • http://about.gitlab.com - we don't need to validate nginx's ability to redirect to https
  • https://gitlab.com/gitlab-org/gitlab-ce
  • https://gitlab.com/gitlab-org/gitlab-ce/issues
  • https://gitlab.com/gitlab-org/gitlab-ce/merge_requests
  • https://gitlab.com/gitlab-org/gitlab-ce/tree/master
  • https://gitlab.com/gitlab-org/gitlab-ce/tree/master - unsure why this one is in here twice...