[x/group] Events

[blushi]

• Add remaining event types for proposals and votes
• We could make the ids (group, proposal...) just uint64 (ref: [x/group] Add amino JSON signing support and CLI #220 (comment))
• We could also add more info to the existing events which are pretty minimalist right now (ref: Add Group module #154 (comment))

ref: regen-network/cosmos-modules#43

[aaronc]

In general I'm in favor of minimalist events which only contain indexable/observable fields, because the other info is elsewhere. So the question should really be - what is a client going to care to observe?