code_relocation: applied ruff code formatting to gen_relocate_app

Ruff is the Zephyr projects supported Python formatting tool. This patch
applies auto-formatting gen_relocate_app.py in preparation for coming
tidy-ups and improvements.

With the Ruff auto-formatter applied, error E501 can be removed from
.ruff-excludes.toml exclusion rules.

gen_relocate_app.py has also been removed from the format exclude list.

Signed-off-by: Joel Holdsworth <jholdsworth@nvidia.com>