Add NAICS / PSC *descriptions* to awards endpoint shapes

[vdavez]

Is your feature request related to a problem? Please describe.
Right now, when I search for a contract, I have to do a separate lookup to get description values for NAICS and PSC. I think that's fine for the default serialization, but we should be able to include that info in the shape.

Describe the solution you'd like
shape=psc(*),naics(*) gets the descriptions and codes

Describe alternatives you've considered
Manual requests to the NAICS/PSC API endpoint and/or caching.

Additional context
N/A