Lint Python code with ruff instead of flake8

[cclauss]

Ruff supports over 600 lint rules and can be used to replace Flake8 (plus dozens of plugins), isort, pydocstyle, yesqa, eradicate, pyupgrade, and autoflake, all while executing (in Rust) tens or hundreds of times faster than any individual tool.

Manually fix these issues...
% ruff rule E402 # Module level import not at top of file

% ruff --select=E401,E722,E741,F524 .

docs/source/conf.py:13:1: E401 Multiple imports on one line
examples/sc2autosave.py:195:13: E722 Do not use bare `except`
sc2reader/engine/plugins/context.py:266:17: F524 `.format` call is missing argument(s) for placeholder(s): 2
sc2reader/resources.py:1494:13: E741 Ambiguous variable name: `l`
Found 4 errors.

Use ruff --fix to fix these issues...
% ruff --statistics .

4	E731	[*] Do not assign a `lambda` expression, use a `def`
3	F901	[*] `raise NotImplemented` should be `raise NotImplementedError`
2	F601	[*] Dictionary key literal `"file_time"` repeated

% ruff --fix .

Found 9 errors (9 fixed, 0 remaining).

[StoicLoofah]

TIL ruff

There's one tweak to the contributing guide to make, but I'll do that by hand on top of this change.

Thanks!