[feature request] werkzeug.contrib.profiler.ProfilerMiddleware custom file name formatting

[ChrisCarini]

It would be nice to allow users to customize the output file name format when using the ProfilerMiddleware.

Currently, the file name format is '%(method)s.%(path)s.%(elapsed)06dms.%(time)d', which when multiple invocations have occurred leads to the profile files being ordered by their respective elapsed times. Having the ability to customize this format allows profiling users to make use of the resultant profile files in additional ways.

I propose the profiler.ProfilerMiddleware is changed to allow users to customize the format of the profile filenames for their specific needs.

[ChrisCarini]

Hey @lepture,

Thank you for labeling with beginner friendly; this is actually my first feature request in werkzeug! I just opened a PR ( #1284 ) with my initial implementation of the change.

Thank you,
Chris