event logger code added

[heypran]

Initial code for livepeer event logger

[ericxtang]

A few comments:

1. The package should have de-duplication when writing into the database, so events won't be logged twice.
2. db should be configurable, so it's not saving to the Admin db.

[heypran]

1. Agree will add that soon
2. I believe it depends on the URI / userRole which someone uses to plugin with this code. As there is no database attached to the code. Its plug and play