Fix #4 #20, Add missing rationale and allow for multiple command counters in requirements

[skliper]

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

• Fix Clarify command counter requirements allow for multiple contexts (tasks) #4
• Fix Fill in missing requirements rationale #20

Testing performed
NA, requirements updates only

Expected behavior changes
None

System(s) tested on
NA

Additional context
None

Third party code
None

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

[astrogeco]

CCB:2022-06-01 APPROVED