These can be sort of arbitrary key-value pairs around one or multiple
runs, handle the following subset:

- when they appear at a paragraph context -> we assume they are
  annotations on the paragraph
- when the smart tag's URI/element is RDF -> we map these to RDF
  metadata statements on paragraphs
- when the attribute name's namespace is known, because in ODF we need
  to specify both a path and a type (namespace) for the RDF graph, and
  OOXML only provides a namespace

As a start, recognize the TSCP BAF namespace from
<https://www.tscp.org/wp-content/uploads/2013/08/TSCP_BAFv1.pdf>.

Change-Id: Ib188b1395e7ec7e0441b4f12f86cfef99fb9f096