Build native executable artifacts

[marcoferrer]

This PR should resolve the existing issues around executing the protoc plugins on windows.
It will allow each of the kroto plugins to behave as a native platform executable. The strategy used is an adaptation of the work being done in salesforce/grpc-java-contrib/canteen

This will also simplify artifact configuration in the protobuf gradle plugin.

Issue #83 should be fully resolved by this.
Issue #6 will be partially resolved.

[codecov-io]

Codecov Report

Merging #87 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master      #87   +/-   ##
=========================================
  Coverage     85.29%   85.29%           
  Complexity       19       19           
=========================================
  Files            15       15           
  Lines           306      306           
  Branches         49       49           
=========================================
  Hits            261      261           
  Misses           16       16           
  Partials         29       29

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b978f5f...29ab6ea. Read the comment docs.