Add init-mmd-prop.rc in case mmd is not built

The build flag RELEASE_MEMORY_MANAGEMENT_DAEMON will be eventually
enabled. If mmd is not built into the image, init-mmd-prop.rc sets
"mmd.enabled_aconfig" sysprop to unblock swapon_all execution.

Devices launching mmd in Trunkfood and Nextfood are supposed to execute
swapon_all command on "on property:mmd.enabled_aconfig=*" trigger.

On devices with mmd enabled, we need `mmd.enabled_aconfig` sysprop to be
empty by default, to let swapon_all command wait until aconfig flag
value is loaded to the system property.

Bug: 393481329
Test: manual

Change-Id: Iaba4cee2b5006a10403d5e03532bed008ab80019