Add encode/decode hooks for TBL services load/dump routines

[jphickey]

Is your feature request related to a problem? Please describe.
Currently, TBL services assumes that the in-memory content of a table structure is identical to the on-disk content of a table file.

However, tables are in many ways analogous to messages, where they are a form of inter-process communication. C structures are not a well-defined data format, they are platform-specific.

Describe the solution you'd like
Data structures in tables should be a well-defined data format, like CMD/TLM messages. As such, table services may need to translate the on-disk data file content into an in-memory representation during load, and vice-versa during dump.

Additional context
This is akin to the encode/decode hooks that were recently added to CI_LAB and TO_LAB. If the content format does match the internal C structure representation, then it is simply a pass-through. However, the code needs to have the appropriate hooks added such that it does not assume it is always a pass-through.

In particular, if a table file format is defined in EDS, then it may require adjustments to padding and byte order during load/dump operations, to work with EDS-compliant binary data files that are independent of the host CPU architecture.

Requester Info
Joseph Hickey, Vantage Systems.