WIP Experiment with gitpod clj

[mrchrisadams]

This PR adds support for spinning up an IDE to in a browser based dev environment provided by gitpod.

It helps demonstrate how you can work in any development environment, and have the notebook-like user experience, using just the clj file, for folks who don't have a clj environnent installed locally.

I haven't quite figured out what the life cycle of moving between next journal and a dev environment fully looks like, but Clerk looks very nice.

Steps to do this

If you're signed up with the hosted version of gitpod.io, you can follow the steps below see what spinning up a dev environment looks like to try this out, by following the steps below:

1. Visit this the link - https://gitpod.io/#https://github.com/mrchrisadams/clerk-demo/tree/experiment-with-gitpod-clj
2. Wait while it builds the dev environment comprised of VS code in the browser, with the Calva extension for clojure, with all the necessary java dependencies (this can be cached but for now, it's best to get a up of tea as it takes about 5 mins)
3. Open dev/user.clj
4. Open the command palette in VS code and choose "Calva: start a project"(
5. evaluate the necessary clojure forms in dev/user.clj (i.e. require the libs, start the fllewatcher, start the webserver)
6. Visit the mapped port for your workspace. (If your browser is at YOUR-WORKSPACE-NAME.ws-eu18.gitpod.io, you visit 7777-YOUR-WORKSPACE-NAME.ws-eu18.gitpod.io (if you can make the webserver listen on 0.0.0.0:7777 then a link is generated for you)
7. Update any of the CLJ files, and watch the changes update in 7777-YOUR-WORKSPACE-NAME.ws-eu18.gitpod.io.