Add extension points to the CLI

[alpe]

CLI was not on my list before for extension points but this may become handy for people working with CLI genesis messages:

// GenesisReader reads genesis data. Extension point for custom genesis state readers.
type GenesisReader interface {
	ReadWasmGenesis(cmd *cobra.Command) (*GenesisData, error)
}

// GenesisMutator extension point to modify the wasm module genesis state
type GenesisMutator interface {
	// AlterModuleState loads the genesis from the default or set home dir,
	// unmarshalls the wasm module section into the object representation
	// calls the callback function to modify it
	// and marshals the modified state back into the genesis file
	AlterWasmModuleState(cmd *cobra.Command, callback func(state *types.GenesisState, appState map[string]json.RawMessage) error) error
}

[ethanfrey]

Looks good. Confused by one level of indirection which may be unneeded. Otherwise great

[codecov]

Codecov Report

Merging #477 (6c89f4f) into master (d9ca5d8) will increase coverage by 0.01%.
The diff coverage is 78.26%.

@@            Coverage Diff             @@
##           master     #477      +/-   ##
==========================================
+ Coverage   56.81%   56.83%   +0.01%     
==========================================
  Files          41       41              
  Lines        4390     4392       +2     
==========================================
+ Hits         2494     2496       +2     
  Misses       1686     1686              
  Partials      210      210              

Impacted Files	Coverage Δ
x/wasm/client/cli/genesis_msg.go	72.18% <78.26%> (+0.21%)	⬆️