Minor updates on the main bridge parts

The two main bridge parts has been improved. The news is a simple system for prevent possible linear bearings slipping out.

Now the bearings needs to be inserted by the same side and a small plastic tab has been added. This tab can be melted with a soldering iron or similar once linear bearings has been inserted. They prevent possible bearings slipping out.
This is only a minor update for new builds and is not a need. If you notice this issue you can probably melt the existing bearing holes or use some epoxy on the existing holes instead to print the new part.

This anti-slippingOut system will be also used on the new carriageV4.