Load settings from environment variables and/or switch off `auto_save_settings` by default

[malmans2]

Is your feature request related to a problem? Please describe.

It would be helpful for us if earthkit would infer cache settings from environment variables. The main reason is that we have many people using the same Virtual Machine.

Also, the current default of settings.auto_save_settings is not ideal for us. If a person plays with the settings (e.g., just copy/paste from the documentation snippets), the settings of everyone using the VM change.

Describe the solution you'd like

Infer settings from environment variables that follow certain rules (e.g., variables with prefix "EARTHKIT_")

Describe alternatives you've considered

No response

Additional context

No response

Organisation

B-Open / CADS-EQC