Generate a man page with the help of the man crate

[alexanderkjall]

Generate a manual page and place it in the generated target directory.

This is useful when packaging the brotli binary in linux distributions, the debian linter lintian complains when there is a missing manual page.

The description of the different options are bare bones at best, it was what I found out by a quick read of the source code. Suggestions of improvements are very welcome :)

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