NEW ISSUE: A single definitions infoset is not sufficient

Title:  A single definitions infoset is not sufficient

Description:
The definitions infoset has a target NS and defines things within that 
target NS. Currently, there is a single global definitions infoset, 
implying that everything must be in the same target NS. This is not 
sufficient as the domain may have QNames (such as intents etc) from 
different namespaces.

Proposal:
Not a clear proposal: but we need to provide a way to have multiple 
definitions infosets.

Note: thanks to Dale for pointing this out.

-Anish
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