add installer script

[alfredodeza]

The idea is that the compiled script will be easy to install, perhaps with curl | bash. In the case of curl, a script needs to be created so that the correct script is pulled in.

An example of this script is here https://github.com/golangci/golangci-lint/blob/master/install.sh

[wagoodman]

This is more easily verified once the repo is made public, so is blocked until that point