Prototype changes for multitree

This change contains a prototype implementation for multitree.
A new file core/tasks/multitree.mk adds a goal named "update-meta",
which searches for "imported" and "exported" Android.bp modules and
writes a json metadata to track dependencies between components.

Bug: 230448564
Test: m
Change-Id: Ie93e3bf130cacb6b6de41acee3bd302f64f1ab95
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 32675f2..65c8ab2 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -169,6 +169,8 @@
 $(call add_json_list, RecoverySnapshotDirsExcluded,      $(RECOVERY_SNAPSHOT_DIRS_EXCLUDED))
 $(call add_json_bool, HostFakeSnapshotEnabled,           $(HOST_FAKE_SNAPSHOT_ENABLE))
 
+$(call add_json_bool, MultitreeUpdateMeta,               $(filter true,$(TARGET_MULTITREE_UPDATE_META)))
+
 $(call add_json_bool, Treble_linker_namespaces,          $(filter true,$(PRODUCT_TREBLE_LINKER_NAMESPACES)))
 $(call add_json_bool, Enforce_vintf_manifest,            $(filter true,$(PRODUCT_ENFORCE_VINTF_MANIFEST)))