Stator clears scope during the main loop to behave more like
transactions. Transaction names are set.
Sentry tags:
* 'takahe.version'
* 'takahe.app' values 'web' or 'stator'
Added settings:
* TAKAHE_SENTRY_SAMPLE_RATE
* TAKAHE_SENTRY_TRACES_SAMPLE_RATE
