Add sending support to courier, plug in sentry, log request and respo…

[nicpottier]

…nse for all incoming/outgoing msgs

[coveralls]

Coverage decreased (-9.8%) to 57.844% when pulling 45eb520 on sending into 7b13ed7 on master.

[coveralls]

Coverage decreased (-15.3%) to 52.314% when pulling d3c3677 on sending into 7b13ed7 on master.

[rowanseymour]

There's a lot in here but it looks good.

Have been thinking about where the responsbility should lie for activating/deactivating channels - e.g. creating callbacks. Let's discuss that sometime.

[rowanseymour]

Not sure how useful it is trying to make channel configs conform to any schema

[rowanseymour]

Coverage down 15% tsk tsk

[nicpottier]

Who needs tests!?! Ya, testing is next, just wanted to cover all the use cases first.

You are talking about who calls Twilio to register the callbacks? Feels like that's a RapidPro responsibility to me but open to discussing it.

[rowanseymour]

Agree that the responsibility lies with RapidPro - see comment on nyaruka/rapidpro#1322 for what I was thinking about activating/deactivating channels

[coveralls]

Coverage decreased (-2.9%) to 64.738% when pulling 161df8e on sending into 7b13ed7 on master.

[coveralls]

Coverage decreased (-1.3%) to 66.274% when pulling c157b9f on sending into 7b13ed7 on master.

[coveralls]

Coverage increased (+0.4%) to 68.0% when pulling 7b2ea69 on sending into 7b13ed7 on master.