init: define 'init_dev_config' service

Instead of letting vendors declare the service themselves, provide a
common service declaration to use by default, including a specific
SELinux domain to control what the process is allowed to do.

The path to the binary to run is configured at build time via the
`ro.vendor.init_dev_config.path' property, which can be set by the
vendor in PRODUCT_VENDOR_PROPERTIES.

The binary MUST rely on bootstrap bionic, given it runs before
apexd-bootstrap, and also labeled as `init_dev_config_exec'.

Bug: 378043923
Bug: 417632996
Test: cvd create & ensure com.google.cf.disabled is not activated

Change-Id: Icd2edd54222e9c142db1d6a590e9789fa06bc378