gkl/obfuscate fs fix: prepend file path to hashed file name to retain fs info

Prepends the file system path to the hashed file name generated by `darshan-convert --obfuscate` so that darshan-parser can still link obfuscated file records to the mounts table.

See merge request !1

This is needed to distinguish between log files generated with
the same job id (i.e., for jobs that have multiple steps)

This function can be called by modules to allow FS-specific
modules to gather data for a given file path/file descriptor.
Currently integrated into POSIX and STDIO modules.

- remaining items are tracked in gitlab issues

- untested

Conflicts:
	darshan-log-format.h
	darshan-runtime/Makefile.in
	darshan-util/Makefile.in
	darshan-util/darshan-logutils.h

There are cases where lustre stripe info is not available the
first time a given file is opened (e.g., when using the
llapi_file_create call). So, now we call into the lustre module
every time a file is opened to give the module a chance to gather
data.