LettuceGrow cover

Occasionally you'll have empty spots on your lettuce grow stand (see lettucegrow.com). This should fit in the hole nicely to cover it.

## Changelog:

### V3
Instead of trying to plug the hole with custom plastic I figured what if we just capped the seed pods, it's functionally equivalent.

### Remix too

Another user has this [awesome option](https://www.thingiverse.com/thing:4834742) and I wanted a single print version of it so I included the remix of their work in here.