kmod-depmod: initial code (no files generated, untested)

kmod-depmod: initial code (no files generated, untested)

this is the initial code for depmod, it should:
 * use configuration from /run/depmod.d, /etc/depmod.d, /lib/depmod.d
 * respect overrides and searches
 * resolve symbols and dependencies
 * break circular dependencies (dependency loops)
 * --errsyms: print out modules with unresolved symbols and incorrect crc
 * --symbol-prefix: respect architecture symbol prefix

it will not:
 * --quick: does not do quick mode
 * --warn: does not warn on duplicates
 * --filesyms: does not load symbols from map file
 * --symvers: does not load symbol versions from map file
 * dump files: does not dump any files at the moment.

it is highly untested, then I appreciate your help with real world
scenarios using overrides and searches. To get output run with -vvvvvv.

next version should fill in the gaps and at least generate the files