add us-west-2 check to API and improve auth repr

[JessicaS11]

Per #231, we've added API access to store._running_in_us_west_2() in the form of a printed statement that the user is (or is not) running in AWS region us-west-2. In the process of implementing this, it became clear that get_edl_token() had not been added to __init__.py, so that was added as well. It also adds a repr for the auth object via a auth.auth_info() property.

I'm seeking input on:

• if this PR fully satisfies [proposed enhancement] AWS us-west-2 checking method #231 - was the spirit to check specifically for us-west-2, or to enable the user to see what region they are running in? Pending that answer, it might make sense to have a more generic earthaccess.region() function instead.
• What should be in auth.__repr__? Currently it's not much better than the object ID:

Authentication Info
-------------------
authenticated?: True
tokens: [{'access_token': 'eyJ0eXAiOiJKV1QiLCJvcmlnaW4iOiJFYXJ0aGRhdGEgTG9naW4iLCJzaWciOiJlZGxqd3RwdWJrZXlfb3BzIiwiY[truncated]...', 'token_type': 'Bearer', 'expiration_date': '02/09/2024'}]

• what tests should we add (if any) for new functions? As best as I can tell store._running_in_us_west_2() isn't tested. Should auth.auth_info() have a dictionary typing/keyword matching test?

[battistowx]

We can probably change the print statement to raise a ValueError with the same message. That way, it is a formal error message that will interrupt the library from opening the bucket out-of-region with a long, cryptic error message.

[JessicaS11]

Thanks to @battistowx during today's earthaccess cowork session for moving this forward with me!

@andypbarrett @betolink Any thoughts on what info we want to be in the auth repr? I'm happy to move that to a separate PR if we want to move forward with the s3check portion of this one.