Add Windows installation

[mabelzhang]

Partially addresses gazebosim/docs#117

Should I target sdf10 or master? Let me know if I need to retarget.

Is ignition-tools an optional dependency? I saw a warning in CMake but didn’t see it in CMakeLists.txt.

I don't have permissions in this repo to request reviewers @chapulina @JShep1

[codecov-io]

Codecov Report

Merging #451 (c55255d) into sdf10 (7dbf121) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##            sdf10     #451   +/-   ##
=======================================
  Coverage   87.54%   87.54%           
=======================================
  Files          61       61           
  Lines        9357     9357           
=======================================
  Hits         8192     8192           
  Misses       1165     1165           

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[JShep1]

Do we want to add Windows binary install also? The package name would be libsdformat<#>

[mabelzhang]

Closing in favor of #463