Add support for /product-services partition

This CL is largely an adaptation of Change-Id
I774e6a38003734421591e51bed103802ff84f432

It adds the following variables:

- BOARD_AVB_PRODUCT_SERVICES_KEY_PATH
- BOARD_AVB_PRODUCT_SERVICES_ALGORITHM
- BOARD_AVB_PRODUCT_SERVICES_ROLLBACK_INDEX_LOCATION
- BOARD_PRODUCT_SERVICESIMAGE_FILE_SYSTEM_TYPE
- BOARD_PRODUCT_SERVICESIMAGE_EXTFS_INODE_COUNT
- BOARD_PRODUCT_SERVICESIMAGE_EXTFS_RSV_PCT
- BOARD_PRODUCT_SERVICESIMAGE_PARTITION_SIZE
- BOARD_PRODUCT_SERVICESIMAGE_JOURNAL_SIZE
- BOARD_PRODUCT_SERVICESIMAGE_SQUASHFS_BLOCK_SIZE
- BOARD_PRODUCT_SERVICESIMAGE_SQUASHFS_COMPRESSOR
- BOARD_PRODUCT_SERVICESIMAGE_SQUASHFS_COMPRESSOR_OPT
- BOARD_PRODUCT_SERVICESIMAGE_SQUASHFS_DISABLE_4K_ALIGN
- BOARD_PREBUILT_PRODUCT_SERVICESIMAGE
- BOARD_USES_PRODUCT_SERVICESIMAGE
- LOCAL_PRODUCT_SERVICES_MODULE
- PRODUCT_PRODUCT_SERVICES_BASE_FS_PATH
- PRODUCT_PRODUCT_SERVICES_VERITY_PARTITION
- PRODUCT_PRODUCT_SERVICES_PROPERTIES
- TARGET_COPY_OUT_PRODUCT_SERVICES
- TARGET_OUT_PRODUCT_SERVICES
- TARGET_OUT_PRODUCT_SERVICES_*

Bug: 80741439
Test: Successfully built product-services.img with one module in it, and flashed
on device. Also successfully built image with /system/product-services directory
and no /product-services partition.
Change-Id: I5d229f6ac729ea6df9ff1f14cee2e28972cd9b4d