Add CMake and other helper scripts needed to build CFE tables

[jphickey]

Is your feature request related to a problem? Please describe.
The scripts to invoke elf2cfetbl were in CFE as part of its cmake logic. This really doesn't belong there, as elf2cfetbl should be responsible for setting up its own targets in the build system to build tables, depending on how the tool works.

Describe the solution you'd like
Move the "business logic" associated with add_cfe_tables() along with any other helper/support scripts to create the intermediate files to this project, not in CFE.

Additional context
The logic of building table files is more closely related to the tool used to build that file, not CFE itself, so it makes more sense to do it here.

A different tool will require different logic and different scripts -- see https://github.com/nasa/EdsLib/tree/main/cfecfs/eds2cfetbl

Requester Info
Joseph Hickey, Vantage Systems, Inc.