update pyproject.toml for ruff format (#48823)

Add ruff configuration to `pyproject.toml`.

This allows `ruff format` in the Spack repository to format all the files we care about, 
with our line length of 99, the exceptions we already put in place, and excluding things
we don't auto-format, like vendored dependencies.

Right now it'll reformat 175 or so files, but only slightly, in places where `ruff` differs from
`black`. For the most part I like the ruff format decisions better than `black`, but none of
the changes seem too severe.

This does not change `spack style` -- I figure that can come later but this at least will
let people start playing with `ruff`.

---------

Signed-off-by: Todd Gamblin <tgamblin@llnl.gov>

lib/spack/spack/package.py

@@ -2,7 +2,7 @@
 #
 # SPDX-License-Identifier: (Apache-2.0 OR MIT)
 
-# flake8: noqa: F401
+# flake8: noqa: F401, E402
 """spack.package defines the public API for Spack packages, by re-exporting useful symbols from
 other modules. Packages should import this module, instead of importing from spack.* directly
 to ensure forward compatibility with future versions of Spack."""