Fix #157, Move function prototypes to header file

[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 #157
  • Moves the function prototypes that were in to_lab_app.c over to the header file

Testing performed GitHub CI actions all passing successfully. Local testing with full cFS suite confirms app performance unaffected.

Expected behavior changes No change to behavior. Makes the file content more consistent with the rest of cFS.

Contributor Info Avi Weiss @thnkslprpt