PerformanceCheck CI Improvements

[runspired]

• use compare instead of HARRemix
• autogen HAR
• use current app always, build assets for other commit and install them as necessary
  • or if we automate publishing canary always test against latest canary
• fix comment post script
• use a secret token with comment permissions so PR's from forks can comment
  • use a check on master with master token to delete comments to avoid giving perms to forks?
    • use check on master only?
• format comment and CI output into easily digestible report (produce our own report instead of using compare:analyze)