Fix #92, Use size_t for 'size' variables

[thnkslprpt]

Checklist

• [x] I reviewed the Contributing Guide.
• [x] I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution Fixes #92 Easy-to-find size variables converted to size_t type.

All except the local variables in FM_ChildDirListPktCmd() and FM_ChildDirListFileLoop() were already of type uint32, so no real risk of signedness issues popping up.

Note: I did not scrub the entire app - if someone can suggest some additional variables to convert over to size_t I can add them to this PR.

A few typos and spacing issues cleared up in the same files.

Testing performed GitHub CI actions (incl. Build + Run, Unit Tests etc.) all passing successfully.

Expected behavior changes Variables representing size should use size_t where possible - more expressive and more compliant with the various (relevant) coding guidelines.

Contributor Info Avi Weiss @thnkslprpt

[dzbaker]

@thnkslprpt CCB 30 March 2023: Approved pending conflict resolution.

[thnkslprpt]

@thnkslprpt CCB 30 March 2023: Approved pending conflict resolution.

All done @dzbaker. Cheers