rfctr(part): remove double-decoration 1 (#3685)
**Summary**
Install new `@apply_metadata()` on CSV and DOCX and remove decoration
from DOC and ODT.
**Additional Context**
- Working in alphabetical order and keeping PR size manageable, replace
use of `@process_metadata()` and `@add_metadata_with_filetype()`
decorators with `@apply_metadata()` on principal partitioners (those
that do not delegate to other partitioners.
- Remove all decorators from delegating partitioners (DOC and ODT in
this case); this removes the "double-decorating".
