Rename system/core/rootdir/Android.mk to create_root_structure.mk

Since Soong currently doesn't support the `install_directory`
functionality, this file cannot be directly converted to Android.bp.
Moreover, the main content of `system/core/rootdir/Android.mk` is to
create directories and symlinks for the root file system. Therefore,
we'll first rename it and move it to build/core/main.mk for handling.

In addition, consolidate the handling of `meta-lic` related parts into
build/core/tasks/meta-lic.mk.

Bug: 353642907
Test: m -j init.environ.rc
Change-Id: I356c4b05c56b02b0243c12dbeddd4653ba4e137c