Image Customisation: Pangeo-style image with VNC/Linux desktop feature

[sgibson91]

This PR attempts to create the desired image for the Alabama Water Institute CIROH hub by following the instructions here: 2i2c-org/infrastructure#1444 (comment)

• Copied Dockerfile from COESSING image: https://github.com/2i2c-org/coessing-image/blob/main/Dockerfile
• Added lines to Dockerfile to install TurboVNC
• Edited environment.yml file to install websockify and jupyter-remote-desktop-proxy

[github-actions]

👈 Test this PR on Binder

[sgibson91]

I am struggling to install TurboVNC with the following error:

  E: Invalid archive signature
  E: Internal error, could not locate member control.tar{.zst,.lz4,.gz,.xz,.bz2,.lzma,}
  E: Could not read meta data from /home/jovyan/turbovnc.deb
  E: The package lists or status file could not be parsed or opened.

[sgibson91]

After 6d4f05c (#1), image now builds successfully in GitHub Actions and on Binder