Add initial support for Bazel --config replacing ENV vars.

Process of removing env variables TF_NEED_GCP, TF_NEED_HDFS,
TF_NEED_GDR, TF_NEED_VERSBS, and TF_ENABLE_XLA. These will be
replaced by Bazel build --config arguments such as
--config=xla.

This CL will make configure support both (env vars and --config)
and will print a deprecation warning if you use env vars.

PiperOrigin-RevId: 168736552