feature request: honor AWS_ENDPOINT_URL, AWS_REGION

[flokli]

I'm trying to use geesefs with a custom endpoint, and was surprised AWS_ENDPOINT_URL and AWS_REGION is not honored.

This was somewhat confusing, as aws s3 commands did work, while geesefs needed --endpoint and --region CLI args (but picked up credentials).

Could you consider adding support?

[levTepl]

in addition to @flokli - geesefs seems to ignore endoint_url from .aws/config file.

User expects a reasonable support of .aws/ configuration directory, endpoint overload is common practice (e.g. for corporate s3, in my case).