Help Wanted: Emphasize in Gitpod docs how to contribute to a plugin project

[mickmister]

Our Gitpod configuration tailors the environment for developing with different plugin projects. Using the Gitpod browser extension, navigating to Gitpod from the given plugin repository creates a Gitpod workspace.

We can emphasize this in our docs, possibly in a different page in the docs than the Gitpod docs page. The page is quite long right now. Maybe we can split it up into different pages in the docs.

Some other related items:

• We can add links to all the plugin project READMEs, to create new Gitpod workspaces
• I'd also like to emphasize that you can open a Gitpod workspace from any PR, by using the Gitpod browser extension, and clicking Open in Gitpod while viewing the PR in GitHub