feat: speed up loading of output data from Terraform state

Description

This speeds up the loading of Terraform outputs (which happens in Instance.tutor_env()). Currently it makes sequential calls to tf output VAR, but each call has some overhead for loading the state. If we instead make a single call to tf output and cache it, we can then access each output in less time.

Using my clipboard_preview instance, before this change tutor_env took ~41s, now it takes ~14s. This is a big improvement in quality of life if you are running lots of grove commands or trying something over and over.

Supporting information

n/a

Testing instructions

Put this into cli.py

@tutor_app.command()
def testenv(instance_name: str):
    """
    Temporary command to get the tutor env
    """
    instance = Instance(instance_name)
    print(instance.tutor_env())

Then run time ./grove tutor testenv SOME_INSTANCE before and after this change.

Dependencies

None

Screenshots

None

Checklist

If any of the items below is not applicable, do not remove them, but put a check in it.

• All providers include the new feature/change
• All affected providers can provision new clusters
• Unit tests are added/updated
• Documentation is added/updated
• The TOOLS_CONTAINER_IMAGE_VERSION in ci_vars.yml is updated
• The grove-template repository is updated

Additional context

Ticket: MNG-3815