Introduce a new proto to capture storage file location for each
container. This proto file will appeara as
/metadata/aconfig/storage_file_location.pb. Storage service daemon is
responsible for writing entires to it when a new storage file set is
available. The flag read lib will use this file to find the
corresponding storage file and mmap them.
Bug: b/321077378
Test: atest aconfig_storage_file.test
Change-Id: I226e76be895805dce52a075050dcd5b42d337be8
Move aconfig storage file definition into its own crate, as flag read
lib will need it as well. The new crate is placed under
aconfig_storage_file dir.
Bug: b/321077378
Test: atest aconfig.test, Cargo test at repo root level
Change-Id: I91e8ada2c9bab479ed81cf03824042f3fa460be5