Automatic merge from submit-queue

Add community expectations about conduct and reviewing.

@sarahnovotny @smarterclayton @philips @thockin @davidopp @jbeda 

As discussed in the previous community meeting here's a description of the expectations around community, I expanded it a little bit beyond code review because it seemed like a good place to put it
down in one location.

Please let me know what I got wrong (or right ;)

Thanks
--brendan