convert license headers to SPDX

Includes license review of 3rd-party files, adding missing upstream
headers, and moving the UNSW OZPLB license into its own file rather
than replicating it in the header.

elfloader: add basic memmove implementation

This is a dumb, unoptimised memmove implementation. It will
use memcpy() where our memcpy implementation will not overwrite data,
but falls back to doing a basic byte-at-a-time copy otherwise.

trivial: style this repo

elfloader: Handle unaligned access for ELF64.

Fix whitespace

- remove trailing whitespace
- remove duplicate blank lines
- remove blank lines at end of file

Updated the hashing process so the user can select hash style (md5 or sha256)

During the build process, the entire kernel and userspace ELF files are run through
the selected hash function and the output is stored as {NAME}.bin, into the CPIO archive.
On the target, the {NAME}.bin files are unpacked with the corresponding
ELF file. The hashes are checked to ensure they are the same.

A hash interface is used to minimize the ifdefs and wrappers needed to get and print
the hashes.

Updated makefile cfiles to build with our hashing source code.

By the way, the elfloader Kconfig isn't accessable in most of these menuconfigs.
Therefore, there are two ways to use the hashing algorithms

1. CONFIG_HASH_INSTRUCTIONS=y in your defconfig
CONFIG_HASH_SHA (optional - remove if you want to md5 hash)
2. Include the elf-loaders Kconfig under a new menu in your top-level Kconfig,
like this:

menu "Tools"
source "tools/elfloader/Kconfig"
endmenu

“Approved for Public Release, Distribution Unlimited”

Initial IBLL Commit.

Modified elfloader to make a hash of the .text section of the elf files
loaded to the target. The build process also makes a hash and loads it onto
the elf. The target then compares the two values to ensure the image got
loaded properly

“Approved for Public Release, Distribution Unlimited”

Fix licenses

elfloader: refactor files to imitate kernel design
- move files to src/include folders
- update files as required, e.g. renaming files and folders to prevent conflicts