Gloomhaven Insert Extras Modification - Card Holder

This is a modified card holder with a couple of minor modifications:

- A "finger hole" to make getting it out of the original insert easier
- A couple of mm thinner floor (and hence the entire part, so the tabs sit a touch lower (I found they were sticking up by a mm or so for me).

The I have re-implemented in OpenSCAD, the source for this is here: https://github.com/sillyfrog/Gloomhaven-Insert-Extras

As part of that I have also included some template left and right tabs/dividers, so it's easy to create more as required.