Adjust the effects of the easy and hard rock mods

[iSimpFor]

currently, easy halves all beatmap setting values and hard rock multiplies all beatmap setting values by x1.4

i would suggest to change the easy mod to subtract 2 points from all beatmap settings and hard rock to add 2 points to all beatmap settings instead of these current effects

this is because easy on high-difficulty beatmaps makes the map harder by increasing map density by lot indirectly by lowering the ar by about half, therefore unintentionally making maps harder than what it's supposed to do
for hard rock, it fixes a problem where if the beatmap setting is at 0, it has no effect on that beatmap setting and if all beatmap settings are at 0, it has no effect on with beatmap expect flipping it upside down

we can then keep the old effects as legacy mods that you access under the respective mod