HDDS-13345. STS port and endpoint skeleton

[len548]

What changes were proposed in this pull request?

Please describe your PR in detail:

• Introduced a new HTTP server on 9880 port
• STS endpoint in the new server with mock return values
• Modification in signature initialization to make it compatible with STS The current signature base creation method expects headers to include x-amz-content-sha256 as payload hash for s3. For STS request, it needs actual payload hash.

What is the link to the Apache JIRA

https://issues.apache.org/jira/browse/HDDS-13345

How was this patch tested?

Unit test and modified existing tests