Update the IEPD Developer training information

[cdmgtri]

A lot of work needs to be done on the IEPD developer training section, including:

• Pick a carefully-constructed, very general example for an exchange.
  • Example should not be too Justice or MilOps-specific.
  • Example should let us demonstrate a lot of key NIEM features like augmentations, associations, metadata, substitution groups, plugging in local code sets, etc.
• Provide a much more detailed walk-through of building an IEPD. Especially in the very NIEM-specific phases like Map and Model, Build and Validate, and Assemble.
• Publish the full IEPD example to GitHub as its own repo.
• Add a walk-through about how to migrate the example IEPD to a new NIEM release.

Note that these updates can be done now but will need to be updated as the new NIEM Message Specification Rules and Guidance and new tools come out.

[cdmgtri]

Pending updated NIEM IEPD developer training, which should be ready this fall.