Cosmos-sdk: Rename hooks to clarify when they will be called

[cwgoes]

OnXYZ() hooks should be called after the relevant operations have completed & results have been written to the store

BeforeXYZ() hooks should be called before the relevant operations have made any updates to the store

cc @rigelrozanski

[rigelrozanski]

Nice - yeah we absolutely need this, not sure on the best naming convention.
On is confusing to me, we should probably just stick to something really obvious like: Before/After or Pre/Post

[jackzampolin]

Really pro Pre/Post I've seen that before in similar situations. Does this work still need to be completed? What are the affected files? I'm happy to take this on.

[rigelrozanski]

All the hooks are in x/staking there is a hook interface within types/ I believe, also in cmd/gaia/app there is some hook stuff... please take it on! I can review you're work to make sure you've caught everything