Add option to use decryption key other than the default

[altinctrl]

Issue

With the latest update to Minecraft Dungeons a new AES key is required to decrypt the pak files.

Solution

By giving the user the option to provide their own key we remove the need to wait for a new release to use the tool and enable it to be used with older versions of the game.

To do

• [ ] Add option to provide new decryption key if default fails #23 #37
• [ ] Add option to relaunch with different pak files and decryption key

[CutFlame]

When I build the releases I include all the AES keys for any of the releases of MCD so the latest version of MCDSaveEdit is already backwards compatible.

[Sebas-Re]

When I build the releases I include all the AES keys for any of the releases of MCD so the latest version of MCDSaveEdit is already backwards compatible.

Yes, that's true, but for example now we have to wait for you to update, while we could just put the new one without bothering you instead.