Add puppet37 to track the 3.7 branch puppet which is still supported

Simplify a bit the Makefile.
Remove patches related to unsupported the legacy package system
Unsilence install target
Merge do-install and post-install which has no reasons to be separated
Switch to full static plist
Keep the broken on ruby22 has I did not had a chance to test on ruby 2.2 yet

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