Add EMC for Powah and Silent's Mechanics.

Given my lack of time and apparently the fact that this mod has updated, I think it may be wiser to suggest additional EMC mappers to https://www.curseforge.com/minecraft/mc-mods/projecte-integration

I may look into adding support for Silent's Mechanisms when I get some more free time (given I will also have to look some into how the mod works to be able to do so, and maybe do it via a PR to that mod). I probably won't bother adding any for Powah, at least not until they update to 1.15, as personally I don't have the time or energy to support multiple versions of MC at once with the amount of time I put into working on Mekanism. So while later today I plan on releasing an update for 1.15.2 for ProjectExtended, it will not have silent mechanisms support initially.

IE (Immersive Engineering) mappers would be great as well.

for advent of acesnion?