Add Gitpod config to project

[ChevronTango]

Gitpod is a widely used Open Source Web IDE that aims to provide easy ephemeral dev environments for projects, which are preconfigured with all the setup done and dependencies already installed. Projects making use of it can find that users are able to develop and contribute against the project much more easily.

In order to support Gitpod for community contributions, a simple config file and a little bit of documentation is all that is required. This config file can run the go commands to install and build the project to allow users to get started with writing the code for their changes.