biqu B1 SE PLUS extend bracket

This is a fix and enahance version of original BIQU B1 SE PLUS extend bracket.

Remix from biqu official extend bracket model, the STL file in the link below.
https://github.com/bigtreetech/BIQU-B1-SE-PLUS/blob/master/B1-SE-PLUS-IDEX%20firmware/Scaffold%20model.STL

Thie original model has 3.5mm hold on the extend bracket, which not fit the screws
provide by original package from "BIQU B1 SE PLUS Dual Z Upgrade Kit/ IDEX Upgrade Kit".
The srcew that come with the IDEX upgrade kit is M3x8 and M3x6, this screw diameter is 3mm, can not screw on 3.5mm hold from original extend bracket.

The new 3d printer user like me, can only know this stl is not useful after you print the official stl privde by BIQU.

So I make new one and move the 4010 fan location inorder to provide better air flow to heatsink on the controller board, also add some cable tie hook for organize cables.
Without those cable block the air flow, heatsink can get better cooling performance.

This other mod