Support .(dot) files in root

When .(dot) file/dir is added to the rootdir, it works with normal `m
systemimage` build, but fails when building the images with target
files because the copy command misses .(dot) files.

When packaging, need to copy the whole content from the src directory.
This also matches the condition `ls -A` (which means, we care about dot
files as well).

Bug: 292438323
Test: m dist (aosp_cf_x86_64_phone-userdebug)
Change-Id: Ib3f555305c915d499448c2064e5639a641b2ddb7