Parametric Bracket Nema

2023-08-31 Remix by https://www.thingiverse.com/DaveX
Copied from https://www.thingiverse.com/thing:2751810

Remixed to change the parameterization to:

* NEMA size,
* wall thickness,
* height offset,
* plus some clearance parameters

... per https://www.thingiverse.com/thing:2751810/comments#comment-6868814 into https://www.thingiverse.com/thing:6196612

Includes STLs for:

| Motor | Round hole STL | Teardrop Hole STL |
|-|-|-|
| NEMA 8, NEMA8, NEMA-8 | Bracket_Nema8.stl | Bracket_Nema8t.stl |
| NEMA 11, NEMA11, or NEMA-11 | Bracket_Nema11.stl | Bracket_Nema11t.stl |
| NEMA 14, NEMA14, or NEMA-14 | Bracket_Nema14.stl | Bracket_Nema14t.stl |
| NEMA 17, NEMA17, or NEMA-17 | Bracket_Nema17.stl | Bracket_Nema17t.stl |
| NEMA 23, NEMA23, or NEMA-23 | Bracket_Nema23.stl | Bracket_Nema23t.stl |
| NEMA 34, NEMA34, or NEMA-34 | Bracket_Nema34.stl | Bracket_Nema34t.stl |
| NEMA 42, NEMA42, or NEMA-42 | Bracket_Nema42.stl | Bracket_Nema42t.stl |

The `Bracket_