Use text token attributes instead of bitfield for file classification

Use text token attributes instead of bitfield for file classification
- 32 bits are nowhere near enough to meaningfully classify all the
  types of data we might want to extract dependencies for, the bitfield
  was already almost used up and twisty with embedded enumeration in the
  middle etc. With text-based tokens, there are no limits to the total
  number of known attributes or number of attributes that can be attached
  to a given file. This also paves way to moving the classification table
  out of librpmbuild into configuration file(s).
- Remove most of the now unused RPMFC_FOO definitions from the FCOLOR enum,
  leaving just the more abstract INCLUDE, WHITE etc which control other
  aspects of the operation. Also ELF is special as the value ends up
  in headers, preserve it too.