[WIP] In-game naval Enigma M4 machine

[gap]

Of course encrypting all the messages would be unrealistic: only campaign messages addressed to the player, intelligence reports and other historical messages sent by/ adressed to U-boats, should be encoded. Most of them are already in the short style described by SkyaBaron. If an automatic encoder is possible, we could choose a tag or a string for marking the messages that actually need to be encoded ;-)