Improve Issue transaction logic for cryptocurrency-advanced [ECR-1132]

[stanislav-tkach]

Currently Issue transaction can be sent by anyone. Its logic should be updated, so that way that this transaction must be signed by the special key stored in the config.

[jgollhardt]

The docs for verifying transactions specify that "This method should not use external data, that is, it must be a pure function."

Wouldn't this require reading a public key from outside the context of the transaction?

I'm probably just missing something.

[stanislav-tkach]

@jgollhardt You are right, technically verify doesn't have access to the database, but the key (or other data) can be stored inside of the global (lazy_static) variable that can be accessed inside the verify method. It isn't an elegant solution, but we use it in several (not public) services.

After #1002 we don't have the verify function anymore, so documentation is outdated (it will be updated soon). Now all checks should be done inside of the execute method.

[jgollhardt]

Ah, that makes sense. Thank you @DarkEld3r !