Drop various patches

This is to trim some patches that are either unnecessary, or superceded, or hopefully superceded (the Minuit disabling):

• I'm not sure the interpreter patch was ever necessary, as perldl has #!perl and is not patched.
• I've updated the Slatec and Minuit code upstream, so those patches won't apply
• this updates the Minuit to try to build (I note the patch to disable it for segfaults was about 2 months ago)

I'm not sure if this is the correct way to achieve this in GitLab terms, or whether I should have updated the changelog as well. The various docs (git and policy especially seemed relevant) don't really give huge guidance on updating packaging, so please let me know what if anything needs doing differently!