Various fixes to MCE Makefile

C modules that contained functionality used both from mce main
binary and plugins were compiled and linked separatedly in mce
and all plugin DSO elf binaries. After the changes they are
compiled once and linked only to mce binary. This reduces both
compilation time and combined binary size by approximately 70%.

Intermediate object files are used instead of compiling and
linking directly from multiple C files. This reduces rebuild
time in case only part of the code base is changed.

Use of actual (autogenerated) header dependencies instead of
triggering rebuild of all C modules also saves rebuild time.

Long lines were split to improve readablity.