Fieldop

[jreadey]

Add support for sub-field selection in hyperslab, point, and query operations for both reading and write.
To specify which fields of a compound type are to be accessed, add a query param or body key of "fields". For a single field selection the query value can just be the field name. If multiple fields are to be accessed, concatenate the field names with a colon separator.

[mattjala]

CodeQL's warning in hsds_logger.py about logging a password seems to be a false positive from printing the username in authUtil.py:321. I think should probably remove it anyway to keep the warnings clean.

The warnings in fileClient also want filepath to be processed to avoid malicious or unusual paths - that should be a quickfix like in the example here.

Besides the CodeQL issues, LGTM.