definitions.mk

This CL lists all the exported platform properties in
private/exported_property_contexts.

Additionally accessing core_property_type from vendor components is
restricted.
Instead public_readable_property_type is used to allow vendor components
to read exported platform properties, and accessibility from
vendor_init is also specified explicitly.

Note that whitelisting would be applied only if
PRODUCT_COMPATIBLE_PROPERTY is set on.

Bug: 38146102
Test: tested on walleye with PRODUCT_COMPATIBLE_PROPERTY=true
Change-Id: I304ba428cc4ca82668fec2ddeb17c971e7ec065e