Create a partial implementation of $PRODUCT_OUT/misc_info.txt

This file is packaged into META/target_files.zip. It is also an implicit
input for `add_img_to_target_files` invocation, which creates additional
metadata files for target_files.zip like apex_info.pb, care_map.pb and
vbmeta_digest.txt

This CL implements the minimum fields necessary to run
`add_img_to_target_files`.

Bug: 399788119
Test: Built target_files.zip locally.
Test: Verified META/misc_info.txt exists, but is not identical to make
Change-Id: I52b9c9ff7b33e74d79b9321aa94312397a830693