Remove support for non-NDK extractor formats

Remove support for intermediate extractor format versions
and leave only the 'V3' format, but remove 'V3' from the
names of the classes and structs involved, and reset the
version number back to 2 (version 1 is the C++ interface
shipped in P, which is no longer supported).

Bug: 111407253
Test: build
Change-Id: I702080e6bbfbac265967a93945ee97191d463125