resolve "convert yarn scripts to Makefile scripts" [#144]

closes #144 (closed)

• make makefile scripts for all yarn scripts
• add aliases for some bash scripts were previously being invoked by ./bin/<some_name>
• group makefile scripts into (tab-completable!) prefixes:
  • _.: high level stuff (installing, updating, building)
  • db.: db-related stuff
  • up./down.: stop/start the app
  • test.: run tests
  • splash.: run and deploy the splash page app