fdgc file cannot be retrieved from a requester-pays S3 Bucket url

[philvarner]

I would expect this to be supported for specifying the fgdc file:

export AWS_REQUEST_PAYER='requester'
stac naip create-item --fgdc s3://naip-analytic/va/2018/60cm/fgdc/37077/m_3707763_se_18_060_20180825.txt \
  VA 2018 s3://naip-analytic/va/2018/60cm/rgbir_cog/37077/m_3707763_se_18_060_20180825.tif \
  json-dest/

however, this fails because the code to read the fgdc txt file doesn't set the requester pays flag on the request, so it returns an access denied message. This is behavior inherited from the pystac io, but it's not really necessary to use that, since we're not retrieving a stac file.

Approach:

1. Use fsspec to retrieve instead of StacIO
2. allow enable of requester pays https://s3fs.readthedocs.io/en/latest/#requester-pays-buckets