重构模式环境的dropPiece和task事件为更强大的自定义和未来联网任意模式做准备

整理出所有模式的这两个事件独立到一个文件夹并整理所有模式引用它们的方式
警告：很可能有错误，需要他人帮助测试

parts/modes/survivor_n.lua

@@ -3,29 +3,7 @@ return{
     env={
         drop=30,lock=60,
         freshLimit=10,
-        task=function(P)
-            while true do
-                YIELD()
-                if P.control then
-                    local D=P.modeData
-                    D.timer=D.timer+1
-                    if D.timer>=math.max(90,180-2*D.wave)and P.atkBufferSum<8 then
-                        local d=D.wave+1
-                        table.insert(P.atkBuffer,
-                            d%4==0 and{line=generateLine(P.holeRND:random(10)),amount=1,countdown=60,cd0=60,time=0,sent=false,lv=1}or
-                            d%4==1 and{line=generateLine(P.holeRND:random(10)),amount=2,countdown=70,cd0=70,time=0,sent=false,lv=1}or
-                            d%4==2 and{line=generateLine(P.holeRND:random(10)),amount=3,countdown=80,cd0=80,time=0,sent=false,lv=2}or
-                            d%4==3 and{line=generateLine(P.holeRND:random(10)),amount=4,countdown=90,cd0=90,time=0,sent=false,lv=3}
-                        )
-                        P.atkBufferSum=P.atkBufferSum+d%4+1
-                        P.stat.recv=P.stat.recv+d%4+1
-                        if D.wave==45 then P:_showText(text.maxspeed,0,-140,100,'appear',.6)end
-                        D.timer=0
-                        D.wave=d
-                    end
-                end
-            end
-        end,
+        eventSet='survivor_n',
         bg='glow',bgm='new era',
     },
     mesDisp=function(P)