* Removes all previous structs that represented an on-disc block layout
and were therfore subject to a number of layout restrictions (packed,
padding members, enum representations, etc.).
* Adds a replacement struct without any layout restrictions for each of the
removed structs. The new structs are named similar to the old structs.
* Adds block encoding and decoding utilities for easily converting from the
new structs to on-disc blocks and vice-versa (Block_scanner, Block_generator,
T::decode_to_blk, T::encode_from_blk)
* Adapts all affected places in the library to encode and decode proberly
instead of simply casting pointers.
* Thereby cleans up the hashing utilities to use typed-reference args instead
of void pointers.
* Re-enables run/tresor_tester and test-file_vault_vonfig_report for platforms
rpi, imx53_qsb, imx53_qsb_tz, imx6q_sabrelite, imx7d_sabre.
Ref #4819
abe163c335