Implement minimal depmod-compatible applet for vx

- Added depmod.cpp to scan kernel module ELF files, read .modinfo, and emit metadata files.
- Implemented functionality to write binary trie indexes for libkmod/modprobe.
- Introduced command-line options for module processing.
- Created test script test_depmod.sh to verify help and version commands.

meson_options.txt

@@ -15,6 +15,7 @@ option('utils',
     'xargs',
     'lspci',
     'setpci',
+    'depmod',
   ],
   description : 'Utilities to include in vx (default: all)'
 )