Heltec V2 or V3 OLED LoRa Case (remix)

Thanks to adamziegler for the original. I have both v2 and v3 heltec LoRa boards, so I wanted ot make sure it fit either.
I've made a number of tweaks to Adam's version, namely:

• Increased thickness of case, to allow a bit more room for battery and cables, allowing a snug fit.
• Added some littel shoulders for the board to sit on.
• Added a little slot in the case for easier opening.
• Increased the cutout on the back for the battery connector, to allow a better close.
• Moved the USB slot up a bit to align and added some external thinning to make the cables fit nicer.
• Modified the buttons so that they aligned with where the board now sits.