AK3: add per-partition attributes, multi-partition fixes

- attributes function now runs via core in setup_ak and reset_ak, but only if it exists, allowing more easy removal of it for setups with no ramdisk changes (so all should now remove the awkward `&& attributes` call from anykernel3.sh, see next commit)
- for multi-partition zips with multiple ramdisks requiring different files, multiple attributes functions may now be specified, either redefine attributes() in anykernel.sh for the next partition, or add a different function for each partition, e.g. boot_attributes() and vendor_boot_attributes()
- fix block=auto multi-partition setup creating an "auto-files" directory instead of final found block, e.g. "init_boot-files"

META-INF/com/google/android/updater-script

@@ -3,4 +3,4 @@
 # Dummy file; update-binary is a shell script (DO NOT CHANGE)
 #
 #
-# AK_BASE_VERSION=20230801
+# AK_BASE_VERSION=20230810