Adjust log groups, stream names

[rclark]

We want to get gitsha's out of our log group names, so that log groups persist between deploys. Will still want the gitsha involved in the mix, so later on we can deduce what version any set of logs came from.

1. Remove the serviceVersion from the log group's name.

2. Change the stream prefix so that it includes the gitsha.

cc @mapsam @yhahn

[GretaCB]

Happy to lend a hand here, esp as I learn more about metric-ifying

[mapsam]

@rclark do we need to also remove the options.serviceVersion from the LogGroupName of the Logs::LogGroup?

[rclark]

Yes! In fact, here were I originally linked we should probably be using a cf.ref or cf.getAtt to grab the log group's name instead of repeating the same thing twice.

[mapsam]

using a cf.ref

Good idea, on it.

Seeing awslogs-stream-prefix in two places as well, for the worker and watcher. Same thing?

[rclark]

Yes please!

[mapsam]

@rclark can this be closed now that #129 has been merged?