This header is used by waf to contain the generated version macros,
particularly using the git hash. For waf it's better to be in a separate
header since it then can keep track of changes on it a trigger
recompilation.
For the make build system, a dummy ap_version.h file has been added in
the missing/ folder so both implementations can co-exist.
Having the version macro in the config.h and consequently in the main
vehicle header means that whenever the version changes we need to
compiler the whole vehicle again. This would not be so bad if we weren't
also appending the git hash in the version. In this case, whenever we
commit to the repository we would need to recompile everything.
Move to a separate header that is include only by its users. Then
instead of compiling everything we will compile just a few files.
