gh-146609: Add colour to timeit CLI output

[hugovk]

Standard and verbose:

./python.exe -m timeit "'-'.join(str(n) for n in range(100))"
./python.exe -m timeit --verbose "'-'.join(str(n) for n in range(100))"

With a warning:

./python.exe -m timeit --verbose "import time, random; time.sleep(random.random() * 0.5)"

As usual, environment variables can control colour output.

• Issue: Add colour to timeit CLI output #146609

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