Add sudo and execute proposal types

[ethanfrey]

Closes #672
Closes #711

• Define protobuf definitions
• Wire up as proposals in wasm module
• Implement proposal handlers
• Test proposal handlers
• Add cli commands for them
• Add rest handlers for them
• Wire up in cli/rest
• Test cli tooling (manually?)

[codecov]

Codecov Report

Merging #730 (20ed020) into master (74f1221) will decrease coverage by 1.62%.
The diff coverage is 14.14%.

@@            Coverage Diff             @@
##           master     #730      +/-   ##
==========================================
- Coverage   59.95%   58.32%   -1.63%     
==========================================
  Files          49       49              
  Lines        5613     5807     +194     
==========================================
+ Hits         3365     3387      +22     
- Misses       2004     2170     +166     
- Partials      244      250       +6     

Impacted Files	Coverage Δ
x/wasm/client/cli/gov_tx.go	0.00% <0.00%> (ø)
x/wasm/keeper/keeper.go	87.54% <ø> (ø)
x/wasm/types/test_fixtures.go	94.94% <ø> (-0.03%)	⬇️
x/wasm/types/proposal.go	63.19% <7.89%> (-19.44%)	⬇️
x/wasm/keeper/proposal_handler.go	62.58% <60.00%> (+0.68%)	⬆️
x/wasm/keeper/contract_keeper.go	92.30% <100.00%> (+0.64%)	⬆️

[ethanfrey]

@alpe I think this is done and covered with tests. Can you please review and let me know how to test the cli better?

[alpe]

LGTM 🎸
Please update the method doc in https://github.com/CosmWasm/wasmd/blob/master/x/wasm/keeper/keeper.go#L441
as it would not be correct anymore.

If you can add the new types to Governance.md then this would be 🚀

Disclaimer:
I have checked that the CLI commands are listed in wasmd tx gov submit-proposal -h but not executed a proposal

[ethanfrey]

Thank you for the feedback. I have addressed all comments, and also added the funds field to the new execute contract proposal type. I also updated the changelog and this is ready to merge