[CodeView/PDB] Rename a bunch of files.

We were starting to get some name clashes between llvm-pdbdump
and the common CodeView framework, so I took this opportunity
to rename a bunch of files to more accurately describe their
usage.  This also helps in llvm-pdbdump to distinguish
between different files and whether they are used for pretty
dump mode or raw dump mode.

llvm-svn: 291627