This is an early draft proposal POC for the interworx migration intermediate format.

It is purposefully incomplete and overly simplified at this stage.

It uses YAML as the file format, as there are ample coding libraries that work
with it, and it's less cumbersome than json.

Notes:
The overview.yml file just references the individual structure/*.yml and
migrations/*.yml files at this point.  This might mean that it just goes away at
some point, or it might be useful for some reason.  At this point it's
there to provide a "starting point" for looking at what's going on.

The individual structure/*.yml files are separated by concern to maximize simplicity.
The idea is that users should be able to utilize and configure them individually,
rather than having to sort through one large nested file.  This his means
the objects within the definitions must include attributes that identifies the "ownership"
relationships between accounts and domains, databases and accounts, resellers
and accounts, etc.

Validation:
The idea is that each file can be validated to some degree using JSON-Schema.
Yes, a thing designed for validating json can be used to validate YAML, apparently.
There are no schemas defined yet - I'm still making it up as I go w/ this POC example.

The cross-file validation would have to be done by us - possibly unless we
ultimately combine all the files into one mega YAML file (at validation time only),
in which case we may be able to validate the whole thing w/ JSON-Schema
(I don't know if it'd be able to do 100% of what we'd want to validate though).

