Bump to 0.9.10, rename to persona-gmail-bridge

Of note to ops:

- The package name changed from browserid-bridge-gmail to persona-gmail-bridge
- The _rootdir changed from /opt/browserid-bridge-gmail to /opt/persona-gmail-bridge
- The binary changed from bin/sideshow.js to bin/persona-gmail-bridge.js
- The statsd prefix changed from browserid. to persona-gmail-bridge.