Make python style compliant

Brings the python files in this repo into compliance with the
checks in `sel4_tools`.

Convert to SPDX license tags

This includes marking all documentation files CC-BY-SA-4.0.

python-capdl-tool: fix size calculation in allocator tests

python-capdl-tool: jiggle allocator testsuite paddrs to be non-zero

The allocator doesn't actually work if an untyped starts at paddr 0.

python-capdl-tool: fix allocator sometimes losing the final untyped

python-capdl-tool: add untyped allocator

This change adds an offline allocator for calculating untyped
derivations, which will be used in future to specify exact derivations
from boot info untyped objects. This allows the allocation logic to be
removed from the loader, this simplifying the loader model for
verificaion while allowing for policy freedom in terms of allocation.

The initial allocator implementation is a best-fit allocator.

Revert "python-capdl-tool: add untyped allocator"

This reverts commit 1b369bbe54cb57a2169e2fe659936844e4d23990.

python-capdl-tool: add untyped allocator

TODO context