TBR: js.syncbase: Prepare all repos for open-sourcing.
TBR: js.syncbase: Prepare all repos for open-sourcing.

The CONTRIBUTING file is added to all repos, and also added
to the jiri-copyright tool so that repos can be automatically
checked and fixed.

I've run jiri copyright fix against all repos to fix up
outstanding issues.

MultiPart: 9/23

Change-Id: Ie4f163d9ef963b1e646a06cecef9a9b536395aad

vanadium/js.syncbase,vanadium/js.syncbase