HDDS-14150. [STS] Connect STS Endpoint to Backend Processing

[fmorg-git]

Please describe your PR in detail:

• This PR was originated from HDDS-14150. [STS] Connect STS Endpoint to Backend Processing #9654 which was getting too big. It has known deficiencies that will be fixed in subsequent PRs.
• Connect S3 Gateway STS Endpoint to Backend OzoneManager Processing
• Add configuration flag check in OzoneManager so STS assume role call is disallowed if configuration flag is not true. Also ensure non-native authorizer is being used as well.
• A future PR will revamp the error handling so that it returns XML instead of plain text
• A future PR will add audit logging in both S3G and OM and correlate the requestId in both.
• A future PR will move duplicate constants and STS validation methods from the endpoint and backend OzoneManager to a shared location.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-14150

How was this patch tested?

unit tests and smoke tests