Support /product partition

This CL adds the following build flags to support building product partition
from Android build system.
- BOARD_AVB_PRODUCT_ADD_HASHTREE_FOOTER_ARGS
- BOARD_AVB_PRODUCT_KEY_PATH
- BOARD_AVB_PRODUCT_ALGORITHM
- BOARD_AVB_PRODUCT_ROLLBACK_INDEX_LOCATION
- BOARD_PREBUILT_PRODUCTIMAGE
- BOARD_PRODUCTIMAGE_EXTFS_INODE_COUNT
- BOARD_PRODUCTIMAGE_FILE_SYSTEM_TYPE
- BOARD_PRODUCTIMAGE_PARTITION_SIZE
- BOARD_PRODUCTIMAGE_SQUASHFS_BLOCK_SIZE
- BOARD_PRODUCTIMAGE_SQUASHFS_COMPRESSOR
- BOARD_PRODUCTIMAGE_SQUASHFS_COMPRESSOR_OPT
- BOARD_PRODUCTIMAGE_SQUASHFS_DISABLE_4K_ALIGN
- BOARD_USES_PRODUCTIMAGE
- LOCAL_PRODUCT_MODULE
- PRODUCT_FOOTER_ARGS
- PRODUCT_PRODUCT_BASE_FS_PATH
- PRODUCT_PRODUCT_VERITY_PARTITION
- TARGET_COPY_OUT_PRODUCT
- TARGET_OUT_PRODUCT*

And PRODUCT_PRODUCT_PROPERTIES is added to save product-specific
properties in /product/build.prop.

Bug: 64195575
Test: succeeded building product.img with BOARD_PRODUCTIMAGE_PARTITION_SIZE,
BOARD_PRODUCTIMAGE_FILE_SYSTEM_TYPE and PRODUCT_PRODUCT_VERITY_PARTITION.

Change-Id: I774e6a38003734421591e51bed103802ff84f432
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 2fa7ad4..639b019 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -124,7 +124,7 @@
 $(call add_json_bool, Uml,                               $(filter true,$(TARGET_USER_MODE_LINUX)))
 $(call add_json_str,  VendorPath,                        $(TARGET_COPY_OUT_VENDOR))
 $(call add_json_str,  OdmPath,                           $(TARGET_COPY_OUT_ODM))
-$(call add_json_str,  OemPath,                           $(TARGET_COPY_OUT_OEM))
+$(call add_json_str,  ProductPath,                       $(TARGET_COPY_OUT_PRODUCT))
 $(call add_json_bool, MinimizeJavaDebugInfo,             $(filter true,$(PRODUCT_MINIMIZE_JAVA_DEBUG_INFO)))
 
 $(call add_json_bool, UseGoma,                           $(filter-out false,$(USE_GOMA)))