Send version in PIN_DB pubsub message

[oed]

Right now the pinning-server has no way of knowing what version of the 3box-js library that is sending the PIN_DB message. We should send along the version in this message for easier upgrades in the future.

[oed]

It's also a good idea to add this to our analytics tracking.

[c-castillo]

@oed if it's on the payload, it will be recorded all the way to the warehouse. Only thing that will need to change is the query in order to have that available

[oed]

ok, great!