doxygen: Upgrade to version 1.11.0

[joerg]

Summary

This upgrades doxygen to version 1.11.0.

I don't know why the FreeBSD patches all used to use QCString for the MD5 buffer rather than plain char, but I kept the patches that way.

[diizzy]

This fails in Poduriere and there's no need to open two reports, just stick with PR 279330
I've submitted an alternative patch (feel free to add back the libmd stuff), it came about 1 hour later because of the testing in Poudriere...