slicot: Move from base

Copied as-is from https://github.com/Homebrew/homebrew/blob/master/Library/Formula/slicot.rb
Needs tests, shared library and other future improvements, but more appropriate here

Do we add it here first, then submit a PR deleting it from base to remove the conflict? Some people in the Julia community can hopefully help make some improvements here.

Original submission to base was here https://github.com/Homebrew/homebrew/pull/16059