Upstream Supply Offsets feature to the SDK

[ValarDragon]

Background

We should upstream our bank supply offsets feature to the mainline SDK. This will help keep the feature parity difference between our forks more in line.

• Bank Supply Offsets
  • feat: Add Supply Offsets to bank module cosmos-sdk#119
  • fix: Add supply offsets to genesis cosmos-sdk#253
  • fix: rest query total supply of cosmos-sdk#275

Suggested Design

Cherry-pick / otherwise copy over changes to SDK. Need to understand if theres any acceptance criterion SDK would have.
Only request from SDK team here relevant to this feature, is if were upstreaming things like this, trying to prioritize getting proto compatability with what we shipped in Osmosis, even if field numbers may not align as conveniently. (In this case I don't think this applies, as we only add a field to genesis, which should have no conflicts with SDK, and we don't really care about)

Acceptance Criteria

• Bank Supply offsets upstreamed to the SDK (or SDK team has expressed interest in not using them)