Updated readme.md with Chocolatey Install Instructions for #566

[digitalcoyote]

Added Chocolatey Install Instructions

[digitalcoyote]

This adds instructions for the Chocolatey Installation method requested in #566

Waiting on Chocolatey moderators to approve the package before marking this as ready for review.

[digitalcoyote]

I need to update a couple fields that changed during package review. and then this will be ready, but the package is approved. https://chocolatey.org/packages/bonobo-git-server/6.5.0

[digitalcoyote]

Let me know if anything looks incorrect, needs more detail, etc. The Chocolatey reviewers prefer to have exactly which prerequisites are setup by the package and a description of what happens at uninstall, but I left it out since it is listed under the manual install instructions.