Cleanup query api

[ethanfrey]

• Targeted PR against correct branch (see CONTRIBUTING.md)

Closes #49

• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Wrote tests
• Updated relevant documentation (docs/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer

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For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• Reviewers assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[codecov-io]

Codecov Report

Merging #50 into master will not change coverage.
The diff coverage is 75%.

@@           Coverage Diff           @@
##           master      #50   +/-   ##
=======================================
  Coverage   63.39%   63.39%           
=======================================
  Files          14       14           
  Lines        1101     1101           
=======================================
  Hits          698      698           
  Misses        337      337           
  Partials       66       66

Impacted Files	Coverage Δ
x/wasm/internal/keeper/genesis.go	0% <0%> (ø)	⬆️
x/wasm/internal/keeper/keeper.go	67.46% <100%> (ø)	⬆️
x/wasm/internal/keeper/querier.go	26.13% <100%> (ø)	⬆️

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