Add Gitpod config file

[MatteoGheza]

I use Gitpod when I have to test some software before installing on my dev machine or when I have to do some basic fix (like fixing a typo). I added a custom Gitpod config (.gitpod.yml and a custom Docker image at .gitpod.Dockerfile). It's very fast at installing dev dependencies, and it should be faster enabling Gitpod prebuilds. BTW, Gitpod it's free if you use it for less than 100 hours monthly, and it's an open source piece of software.

Here I attach a demo video (please ignore the "Nx Console" popup, it's installed on my account).

https://user-images.githubusercontent.com/27729549/153942440-814cfb26-4ec5-495b-b316-90fd5e324ad7.mp4

[CLAassistant]

All committers have signed the CLA.

[josephdadams]

We use this with Tally Arbiter and it's pretty nice. @MatteoGheza set it up for us there.

[MatteoGheza]

Now it should work. Fixed a bug with NVM. Now it installs the Node version defined in .nvmrc

[Julusian]

I haven't forgotten about this PR, but I am having trouble understanding the value of supporting gitpod with it unable to serve both the ui and backend.

If it can be made to serve the ui and for that to talk to companion correctly, then I think this has some value and I am ok with merging it.

If we need to do a small check to disable the cors check under certain conditions then that is ok with me. Perhaps when the DEVELOPER variable is set, as well as another variable (DISABLE_CORS_CHECK?)

[Julusian]

This has been sat stuck for far too long now.

I am still struggling to see the value of this in its current form. Not being able to serve the ui in development mode is a deal breaker to me, as that would severely limit what could be worked on with this.
Overall, I am not opposed to this, but it needs this ui serving for me to be willing to merge it. Hopefully that is as simple as needing to mess with CORS settings as I suggested above.

If someone is willing to figure this out, please do submit a new PR