Allow Wildcard for H2O_WAVE_ALLOWED_ORIGINS

[maxjeblick]

Is your feature request related to a problem? Please describe

I'm using LLM Studio with port forwarding on a cloud instance. The dynamically generated link to access localhost:10101 varies for each run. Currently, I need to

1. Start the instance
2. Manually copy the link that forwards 10101
3. Log into the cloud instance
4. Set export H2O_WAVE_ALLOWED_ORIGINS="https://..." (note that the link needs to be without / at the end, this took me a while to figure out. Maybe trailing / can be removed automatically?)
5. Start wave

Describe the solution you'd like

I'd like to use export H2O_WAVE_ALLOWED_ORIGINS="*" to be able to circumvent the process described above (define a dockerfile that will be executed automatically when the instance starts).

This is analogous to jupyter which uses --NotebookApp.allow_origin='*'.

Describe alternatives you've considered

See steps 1-5 above

Additional context

This issue has been mentioned several times for h2o-llm-studio, see e.g. here