Add *_dlkm properties to android.ModuleBase

To aid mk->bp migration of (system|vendor|odm)_dlkm.img files,
https://r.android.com/3331335 introduced properties to prebuilt_etc to
allow installation of soong etc modules in these partitions. The dlkm.img
files package .ko files and build.prop files. The current plan is to use
`prebuilt_kernel_modules` soong module type to package the .ko files and
create additional modules.* metadata files.

To aid this migration, this CL moves the _dlkm_specific properties to
android.ModuleBase and updates `modulePartition` to return the
corresponding dlkm partition.

Bug: 377562851
Test: m nothing --no-skip-soong-tests
Test: m installclean && m fs_config_files_system_dlkm
verified that $PRODUCT_OUT/system_dlkm/etc/fs_config_files exists

Change-Id: Ia398a85a9a2b81532871a5ab88454317039f44b9