Peggy Stargate migration and code clean up

[jackzampolin]

Ok! So we have a building peggy sdk@v0.40.0-rc3 (🌟 Stargate 🌟 ) version 🎉 🚀 🙌 🧑‍🚀 The following are remaining TODOs for the stargate work in the rough order I think they should be tackled in:

• audit types in ./proto to ensure that naming is consistent and types have necessary information
  • Update type props in rust module/x/peggy/keeper/querier_test.go in this PR has the field changes
• tests passing ./x/peggy/types/..., main issue here is ethereum address encoding/decoding
  • TestValidateMsgSetEthAddress failing, signature needs to be updated
• tests passing ./x/peggy/keeper/... main issue here is formatting of the querier returns
  • TestAllValsetConfirmsBynonce failing, iterator not working properly
• tests passing in ./x/peggy/... handler test issues will likely be resolved by fixing /types and /keeper tests
• Refactors:
  • Remove BridgeDenom
  • Remove VoucherDenom
  • Remove Uint64Nonce
• e2e peggy tests passing
• gRPC query implemenetation
• gRPC tx implementation
• simulation for the peggy module and wire up those sims to CI
• implement invariants for peggy if applicable
• reimplement the CLI with full peggy functionality

[jackzampolin]

Ok, since I've now got the gRPC stuff implemented (tx side only stubbed out for now cause we don't have a usecase) I'm marking this r4r. Would like to get #114 and #118 into this PR before merge too

[jkilpatr]

closed in favor of #120