Makefile improvements

[RiccardoM]

Description

Improved how Makefile is written, including the contrib/devtools Makefile which allows for easy golangci-lint tools to be downloaded and installed.

Checklist

• Targeted PR against correct branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Wrote tests
• Re-reviewed Files changed in the Github PR explorer

[codecov-io]

Codecov Report

Merging #44 into develop will not change coverage.
The diff coverage is 0%.

@@           Coverage Diff            @@
##           develop      #44   +/-   ##
========================================
  Coverage    81.47%   81.47%           
========================================
  Files           13       13           
  Lines          502      502           
========================================
  Hits           409      409           
  Misses          84       84           
  Partials         9        9

Impacted Files	Coverage Δ
x/magpie/internal/types/msgs.go	96% <ø> (ø)	⬆️
x/posts/internal/keeper/keeper.go	100% <ø> (ø)	⬆️
x/posts/internal/types/post.go	4% <0%> (ø)	⬆️

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