Adapt to work remotely

[victor141516]

Closes #160

I changed a few things:

1. Make WebSocket URI dynamic based on the current URL
2. Some improvements on the Dockerfile*
3. Add a button to download the compiled file after the build

Example using a remote server:

Screen.Recording.2022-08-06.at.03.27.32.mov

*I don't know if you had npm install as part of the CMD for a reason I currently don't understand. I moved it to the build part