Fix #51, add monitor table

[jphickey]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• 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
Replace the "free space" table with a more general disk monitoring table, which can have entries for volume free space (which is what was there) as well as an estimate of directory usage.

Table and TLM was renamed accordingly. This changes the definition of the TLM report to include the extra info, so it requires a ground system update.

Fixes #51

Testing performed
Build and run FM in CFE, issue "monitor" command (16) and confirm correct/expected TLM is sent
Run all tests, confirm 100% coverage

Expected behavior changes
The "free space" command is replaced with a more general "monitor" command that allows for multiple types/flavors of monitoring. The VOLUME_FREE_SPACE type implements the same logic as the original free space table/command, and the newly added DIRECTORY_ESTIMATE type implements the request in #51.

System(s) tested on
Ubuntu 22.04

Additional context
This is effectively replacing the old free space TLM packet (FM_FREE_SPACE_TLM_MID) with a monitor report TLM that is more general. Notably, it contains a type indicator, and it can report either space used or space free depending on type.

Contributor Info - All information REQUIRED for consideration of pull request
Joseph Hickey, Vantage Systems, Inc.

[dzbaker]

CCB 27 October 2022: Approved pending workflow failure resolution

[jphickey]

I checked into all of the failures reported during the workflow runs, and nothing appears to be caused directly by this change. They all look like unrelated issues.

Note that the parent workflow recently switched from using Ubuntu 18.04 -> 20.04 for the builds, and thus is using a new version of the gcc compiler. This produces more warnings than the old one did, and it is now flagging a suspicious-looking use of strncpy() ... the code is probably actually OK here, because the length is checked before the call, even though it looks like a common coding error was committed here.

Similarly, the new static analysis errors are also triggered by using a newer version of the tool.

All of these workflow errors should probably be addressed in separate issue tickets, but it shouldn't hold up merging this one.