HEVO Y carriage for 2020 / 1515 extrusion profile

edit: 07/19 : Added version for LM8(L)UU-2020-F694 version on a request.

edit: 04/08/19:
- Added Y endstop flag
- Fixed pulleys position both variants
- Pulley pockets for the F694 variant changed to "trough all" to allow using screws (or dowell pins)
- Added 0.8mm space to the pulleys posts for the F694 variant to allow for a 4mm ID washer in between to avoid belt protrusion..

edit: 03/