[WIP] Add script to start/stop rippled

[WIP] Tweak script
* Use `node bin/stop-test.js 5,10` form instead of ENV_VAR
* Log the rippled  pid
* Don't abort on stalls unless an environment variable set

[WIP] Tweak logging

[WIP] Fix

[WIP] Run through the range again on completion

[WIP] Tweak so can use non integer range elements