Add tool to package up built modules.

With this change, you can package up modules while avoiding installing
them to the system.img or userdata.img.
- build/core/tasks/tools/package-modules.mk
  You can use this template to package up modules into a zip file and
  preserve the installed file paths.
- LOCAL_PICKUP_FILES, you can use this variable to package up extra
  files/directories.

Bug: 13585955
Change-Id: I103042b24ccf17cf5dc90c016d97ed1dd293e50b