Split header files into external and internal components

[jphickey]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I reviewed the README file to see if the feature is in the major future work.
• I performed a cursory search to see if the feature request is relevant, not redundant, nor in conflict with other tickets.

Is your feature request related to a problem? Please describe.
Configuration and header files for this app currently have mixed scope - some items apply globally (mission) and some only affect the internal app behavior.

Describe the solution you'd like
Split headers into single scope, so they contain only public/global items (i.e. those that affect CMD/TLM/Table definitions) or they contain private/internal items. The latter would be things that are only used within the local application code and do not affect the interface.

Additional context
Similar to nasa/HS#84. This helps stabilize the interface, so configuration items that do change the interface are clearly marked in a separate file and the user is more aware of the impact the changes will have. It's also important for EDS, where some of these files are generated - keeping a single scope allows for simple source selection vs. #ifdefs.

Requester Info
Joseph Hickey, Vantage Systems, Inc.