Having a non-sudo, easy way to locally deploy the GTN

I had a lot of problems deploying the GTN locally on my managed laptop, without admin rights (so no `sudo`). Github codespaces was of help (but is limited in time, not local, Github dependent,...) but believe that a local, more OS-agnostic, non-sudo way of statically building the website should exists out there (devcontainers?) which would be of tremendous help to lower the barrier for contributions (in my humble perspective).

I would like to take a look myself and see if it's possible and ideally contribute it back [here](https://training.galaxyproject.org/training-material/topics/contributing/tutorials/rendering_gtn/tutorial.html) one day but already putting the issue out there for anyone else to check out and perhaps contribute to.

Related to https://github.com/galaxyproject/training-material/issues/5841#issuecomment-4801003955.

Start with the rendering GTN tutorial linked in the issue and compare its local deployment steps with GitHub Codespaces. Investigate whether a non-sudo, OS-agnostic static build using devcontainers is feasible; done means contributors can build locally without admin rights.

Written by the indexing model from the issue text.