Consolidate access= and in_region= kwargs?

[jrbourbeau]

Following up on #318 (comment)

I'm not sure why we have separate access and in_region kwargs for determining if we want to use s3 or https urls. Is one kwarg sufficient?

I think we want to, by default, use S3 access when on AWS in region us-west-2 and https paths otherwise. Based on

earthaccess/earthaccess/results.py

Lines 315 to 317 in 6fbc4ae

	# Even though we are in us-west-2 the user wants the HTTPS links
	# used in region they are S3 signed links from TEA
	# https://github.com/asfadmin/thin-egress-app

it looks like we also want the ability to override this default for some special cases (seems reasonable). I think we can accomplish this with a single access= or in_region= or some other name kwarg.