Rewrite keeping some aspects but changing many to be more like I expected the original plugin to work

Changes include:

No longer round up to Gold medal Added a slider to change the percentage time improvement you want to target (was previously hardcoded) This one's pretty exciting: Works on all maps, not limited to TOTD anymore!

Some differences to note: The original had some logic which looked at your previous times and calculated the improvement target based on that, but personally that seemed to often overestimate your skill level so just manually specifying a target seemed like a good compromise