This has better multi-core performance and can run in persistent mode -- which
allows us to construct a test harness of all the parsers (which takes time) and
then just reuse the process for lots of different data.
To do this mount all ESP partitions and check all the binaries there to see if
they match any entries in the new dbx. If we applied the update when a hash
matched, we would unintentially 'brick' the users machine, as the grub and shim
binaries *have* to be updated first.
This functionality does reimplement the PE hashing functionality found in
sbsigntools and pesign. This was done for 4 main reasons:
* There were some memory safety issues found when fuzzing random binaries
* Executing the tools hundreds of times was a lot of overhead
* Operating from a blob of immutable mmap'd memory is much faster
* We only need a very small amount of functionality from both tools
