Fix #131, Reset file psn and use OS_mv for out-of-order RX MD processing

[skliper]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I signed and emailed the appropriate Contributor License Agreement to [email protected] and copied [email protected].

Describe the contribution

• Fix Likely issues in processing of deferred/reordered "md" packets #131

Switches from OS_rename to OS_mv which supports "rename" across file systems (via copy/delete)
Resets file cached position (from the file open) so it gets recalculated correctly

Testing performed
CI (added unit test asserts)

Expected behavior changes
Should now handle an out-of-order MD, and a tmp dir being on a different filesystem than the final location

System(s) tested on
CI

Additional context
Note the functional/CTF test is the full verification of this capability

Third party code
None

Contributor Info - All information REQUIRED for consideration of pull request
Jacob Hageman - NASA/GSFC

[skliper]

Note 8855399 adds operational temporary file documentation (no code changes).