Anet A8 X Axis Belt Tension System - Minimized for IKEA Lack enclosure

I think this design from [s34n72](https://www.thingiverse.com/thing:2585667) is the best X axis tension system for the Anet A8, but it was too wide to fit in the IKEA Lack enclosure.

This is why I made some modifications to make it a lot smaller without disrupting the functionality or strength of the design.

Parts:
- Knob: Edited to make it a lot smaller.
- Block: Original from s34n72.
- Puller v2: Original from s34n72.

Needed materials (just like the original design):
- 2x M5 bolt