sanitize-commit: Validate QUIP footers

Like for other footers, complain if

- the capitalization is wrong

- more than one QUIP is listed per line

- the QUIPs are not numerical (catching QUIP: QUIP-0004)

Unlike Coverity-Id, there is a tradition to write QUIP numbers with
leading zeros (QUIP-0004), so allow that here.

Task-number: QTQAINFRA-7033
Change-Id: I8a2302054f3205d8c1777c42f28671de79812c20
Reviewed-by: Daniel Smith <daniel.smith@qt.io>