ensure configure works with existing install

[matt-long]

Many people may already have Python setup. Is the configure script robust in this context?

[andersy005]

This is being handled by:

ncar-python-tutorial/setup/configure

Line 44 in 0753eee

conda_path = detect_existing_executable("conda")

ncar-python-tutorial/setup/configure

Lines 55 to 60 in 0753eee

	if conda_path is not None:
	print(
	f"************** Found an existing Conda installation at: {conda_path} **************"
	)
	print("***************** Skipping Conda installation... *****************")

ncar-python-tutorial/setup/configure

Lines 80 to 85 in 0753eee

	print(
	"************** Creating/Updating conda environments (this can take 5-10 min) ***********"
	)
	env_update_script = os.path.join(here, "create_env")
	run_script(env_update_script, my_env)

When a conda installation is available, we proceed to updating the analysis environment if it exists, if it doesn't, we create it.

I tested this on my laptop yesterday. I will test it on Cheyenne as well.

[andersy005]

Addressed in #59, and other previous PRs.