ENH: add Cookiecutter instructions to plugin dev docs (#80)
ENH: add Cookiecutter instructions to plugin dev docs (#80)

Removes `qiime dev plugin-init` instructions in favor of using Cookiecutter directly.
jairideout/docs,gregcaporaso/docs,gregcaporaso/docs,jairideout/docs,qiime2/docs,jairideout/docs,qiime2/docs,qiime2/docs,gregcaporaso/docs