package/python-cryptography: bump version to 36.0.1

This version bump requires significant changes because
python-cryptography is now partially implemented in Rust.

This means that:

 - The C++ dependency is no longer needed.

 - We need to ensure we are on an architecture where Rust is
   available (BR2_PACKAGE_HOST_RUSTC_TARGET_ARCH_SUPPORTS)

 - Almost all Python dependencies are no longer relevant, except for
   the python-cffi.

 - A number of environment variables are needed to make the Rust part
   build correctly.

 - We need to invoke the "cargo" download post-process hook to vendor
   the Cargo dependencies at download time.

 - We need to propagate to relatively significant reverse dependency
   tree the changes of dependencies on python-cryptography.

Co-developed-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>