Add modules partition

Add updateable_module_file that describes all files under /modules. If
more directories (e.g. /modules/apex etc.) are added in the future,
separate labels should be applied to them.

Bug: 163543381
Test: on CF check /proc/mounts

Change-Id: Iceafebd85a2ffa47a73dce70d268d8a6fb5a5103
diff --git a/private/file_contexts b/private/file_contexts
index 27bbb3d..8fa09bb 100644
--- a/private/file_contexts
+++ b/private/file_contexts
@@ -479,6 +479,13 @@
 /(odm_dlkm|vendor/odm_dlkm|system/vendor/odm_dlkm)(/.*)?                  u:object_r:vendor_file:s0
 
 #############################
+# Modules files
+# This includes updateable modules (including APEXes and APKs) that are stored
+# in the modules partition.
+#
+/modules(/.*)?      u:object_r:updateable_module_file:s0
+
+#############################
 # Vendor files from /(product|system/product)/vendor_overlay
 #
 # NOTE: For additional vendor file contexts for vendor overlay files,