Add hooks for pouring bottles.

This should give us a bit of control over what e.g. Boxen are doing
whilst at the same time stopping us from accidentally breaking each
other's stuff every so often.

I'm aware this may be somewhat controversial so I'm open to other
approaches.
Add tests for new bottling hooks.

Closes #27890.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
sync_gateway: 1.0-beta2 - couchbase mobile sync

sync_gateway provides the syncing backend for couchbase mobile and is
used together with couchbase-lite-ios or android to develop syncing apps
for iOS or android.

Since the project itself is named sync_gateway I kept the name for the
formula as well.
fix code style
updated to beta3