Heltec V4 Case

This is a remix of kekityn_'s heltec case. This case supports a board without a screen. The fasteners have been changed so that a M2.5 nut and bolt can be used to fasten the case closed. The tolerances are very tight on the bolt and it is best if you heat set the nuts in place like an insert. Extra space has been provided so that additional telemetry modules can be soldered to the board and still fit inside of the case. This should accommodate a v3 and v4 heltec LoRa board.