Revised kernel printf implementation

Adapted musl printf implementation using our output abstraction.
Floating point specifiers are not supported in this adaptation.
Modified the code to also match our style and make it
less unnecessarily complex.

Signed-off-by: Saer Debel <saer.debel@data61.csiro.au>

userError string written to IPC buffer

The format string in userError is now written to
the IPC buffer for debugging purposes.
This requires an snprintf which reuses vprintf with
a new structure for handling how output is done.

Signed-off-by: Saer Debel <saer.debel@data61.csiro.au>

Convert license tags to SPDX identifiers

This commit also converts our own copyright headers to directly use
SPDX, but leaves all other copyright header intact, only adding the
SPDX ident. As far as possible this commit also merges multiple
Data61 copyright statements/headers into one for consistency.

output: use CR LF as line break and not LF CR

style: consistently attach return type

Add attach-return-type to astyle

style: correct parenthesis padding

Use astyle's unpad-paren to unpad all parentheses that are not included
by pad-header, pad-oper, and pad-comma.

serial: remove putConsoleChar

putConsoleChar was needless indirection around putDebugChar. Remove
this.

[STYLE_FIX]

kprintf: support trailing spaces in format strings

ie %20s, %4lu will now work. Leading spaces won't though.

Fix putchar

SELFOUR-624: fix ia32 debug build

- separate putDebugChar and putConsoleChar
- this only has effect on x86 where 2 serial ports are initialised by
the kernel
- for arm, putConsoleChar just calls putDebugChar

SELFOUR-624: remove redundancy in io.[c|h]

And clean up a bit while we are there

Further separate 'release' and 'verification' builds

Originally building the kernel was largely considered to be done in
one of two ways
1. Release build with no assertions, no debug symbols and no printing.
This was generally considered to be a 'verified' build
2. Debug build with assertions, debug symbols and printing

Since then various options were added, such as the 'code injection'
option, which we wanted on builds that did not have assertions or
other options that affected performance. As such it did not depend
upon a debug build and had large warning signs saying that enabling
this in a release build would not give you a verified or trusted
kernel.

Most recently the ability to print from the kernel in release mode
was added. For the same reason that tying the ability to print with
the performance reduction of various debugging was not always desireable.

This change attempts to unify the current state and have a single top
level option to enable a 'verification friendly' build. All other
options (assertions, printing, code injection) then depend upon
this configuration not being set.

trivial: style

Change additional int->word_t due to interraction with the C parser to ease verification

unsigned int -> word_t

Make utility functions 64bit friendly

add support for %lx, %lu, %ld to kprintf, return -1 if format not supported

xIntroduce RELEASE_PRINTF, which allows a renamed printf (release_printf) to be used in a release build of the kernel - userful for debugging tests that only fail on a release build of the kernel

Release snapshot