boot-utils: Switch to ruff for Python formatting

We started using ruff for linting a while ago. Since then, it has grown
a formatting option, which is quite fast. While it is a little less
flexible than YAPF, we don't currently customize the behavior aside from
some exemptions.

Switch to ruff for formatting. Most of the changes end up making the
code a little more readable, at the expense of some extra lines. Switch
to the generic fmt comments instead of the yapf specific ones. Use the
option to preserve our quoting style, which uses single quotes for
string literals and double quotes for f-string or raw strings.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Author: nathanchance