hardware_product fields need to be dynamic

[karenetheridge]

This is very similar to joyent/conch-ui#293 -- the list of properties expected by POST /hardware_product/* and GET /hardware_product/* are changing, and the individual values used as inputs to validations will be moving into specification and will be even more dynamic. I have added annotations to the appropriate schemas to allow UIs to be built off them dynamically.

[karenetheridge]

Also note that the 'specification' field itself, or even subsets of it, is also editable via its own api endpoint, PUT /hardware_product/:identifier/specification, as it may be desirable to present a separate ability(ies) for the user to edit bits of this.