Fix swagger auth script and documentation

[chmreid]

This PR updates the Readme section about swagger auth, and the script used to update swagger auth.

Summary of readme changes:

• clarify language and descriptions
• update and fix example call to swagger auth script

Summary of script changes:

• add an "auth name" for specifying the name of the auth mechanism, instead of using the hard-coded dcpAuth

closes #105

[chmreid]

merge in once https://ucsc-ci.com/databiosphere/data-store/pipelines/2969 is finished