Fold this into https://github.com/tetratelabs/getenvoy

[codefromthecrypt]

Especially after builds migrate upstream, this repo will only describe the CLI at https://github.com/tetratelabs/getenvoy

Having this split apart has caused needless memory and navigation, including synchronizing files across multiple repos to publish the "latest" version of envoy, confusion about why the download script doesn't exist in the same place as it is published (#157) and even things like markdown generation (tetratelabs/func-e#205)

When you consider the this repo will only describe a CLI with not even 10 commands, the complexity of splitting this into a separate repository is questionable and largely ensures work takes longer and can miss more steps.

I implore us to start hating complexity by allowing this repo to merge with https://github.com/tetratelabs/getenvoy either by a subdir/monorepo style or in worst case gh-pages branch