Fix running a local standalone server

[sbarber2]

Update the top-level Makefile to use standalone.py, etc.

Closes #650

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.36%. Comparing base (3e23ffc) to head (8f6516a).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #651   +/-   ##
=======================================
  Coverage   70.36%   70.36%           
=======================================
  Files          36       36           
  Lines        3884     3884           
  Branches       64       64           
=======================================
  Hits         2733     2733           
  Misses       1126     1126           
  Partials       25       25           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[simsong]

ah, yes, I moved standalone.py out of deploy/app because standalone.py doesn't need to be deployed.

[simsong]

I wonder if we could test this as part of our ci/CD...