drop incorrect information about adding a tool

This repository contains only information about proprietary images.
None of the scripts to add a tool, build and test an image or even most
of the linked documents exist in this repository. Users can only request
a tool, but never add one themselves. There is no need for incomplete
documentation on an imposible process.

CONTRIBUTING.MD

@@ -14,28 +14,15 @@ Please note that this project is released with a [Contributor Code of Conduct][c
 
 1. [Fork][fork] and clone the repository
 1. Create a new branch: `git checkout -b my-branch-name`
-1. Make your changes, ensure that they include steps to install, validate post-install and update software report (please see [How to add new tool](CONTRIBUTING.MD#how-to-add-new-tool) for details).
-1. Test your changes by [creating VHD and deploying a VM](docs/create-image-and-azure-resources.md).
+1. Make your changes.
+1. Test your changes.
 1. Push to your fork and [submit a pull request][pr]
 
 Here are a few things you can do that will increase the likelihood of your pull request being accepted:
 
-- Follow the style guide for [Powershell](https://github.com/PoshCode/PowerShellPracticeAndStyle) when writing Windows scripts. There is currently no set style for the Shell scripts that run Linux installs :soon:.
 - Include complete details of why this is needed in the PR description. 
 - Keep your change as focused as possible. If there are multiple changes you would like to make that are not dependent upon each other, consider submitting them as separate pull requests.
 - Write [good commit messages](http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html).
-- For new tools:
-  - Make sure that the tool satisfies [Software Guidelines](README.md#software-guidelines).
-  - Create an issue and get an approval from us to add this tool to the image before creating the pull request.
-
-## How to add new tool
-### General rules
-- For every new tool add validation scripts and update software report script to make sure that it is included to documentation
-- If the tool is available in other platforms (macOS, Windows, Linux), make sure you include it in as many as possible.
-- If installing a few versions of the tool, consider putting the list of versions in the corresponding `toolset.json` file. It will help other customers to configure their builds flexibly. 
-- Use consistent naming across all files
-- Validation scripts should be simple and shouldn't change image content
-
 
 ## Resources