Update 17 files

- /external/lab-equipment/maintenance-of-fridges/maintenance-of-fridges.md
- /external/lab-equipment/maintenance-of-fridges/freezers-150.md
- /external/lab-equipment/fridges/img/img5.png
- /external/lab-equipment/fridges/img/img6a.png
- /external/lab-equipment/fridges/img/img6b.png
- /external/lab-equipment/fridges/img/img7.png
- /external/lab-equipment/fridges/fridges.md
- /external/lab-equipment/freezers/img/img8.png
- /external/lab-equipment/freezers/img/img9.png
- /external/lab-equipment/freezers/freezers.md
- /external/lab-equipment/ultra-freezers/img/img10.png
- /external/lab-equipment/ultra-freezers/img/img11.png
- /external/lab-equipment/ultra-freezers/img/img12.png
- /external/lab-equipment/ultra-freezers/img/img13.png
- /external/lab-equipment/ultra-freezers/img/img14.png
- /external/lab-equipment/ultra-freezers/img/img15.png
- /external/lab-equipment/ultra-freezers/ultra-freezers.md