Nimble V1 mount for the BLV printer

The New Nimble V2 family is here. [Nimble Version 2 family](https://www.thingiverse.com/thing:3924926)
The Nimble V1 is no longer sold.

Changelog:

-1. Made a little more space in the top righthand corner. The screw should be easier to insert now.

Here is a mount for the NImble, so you can put a Nimble on the lovely BLV printer.
It is complete with a new cover to fit around the Nimble.
All the other parts are left the same and can be used as they are.