Split "platform_cfg" 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.
Currently, all configurable items for the app are contained in a single lc_platform_cfg.h header file. This contains macro definitions that affect both the internal operation of the application (such as operational limits) as well as the external interface in CMD/TLM and table files.

Describe the solution you'd like
Split this header into two components, one that contains only public items (i.e. those that affect CMD/TLM/Table definitions) and one that contains private/internal items that are only used within the local application code and do not affect the interface.

Additional context
Mainly a scoping concern, separate files for separate scopes. These files could also be generated in the future, but scope still needs to be consistent.

Requester Info
Joseph Hickey, Vantage Systems, Inc.