Add option for disabling diamond chestplate

[DrHenchman]

This option should be disabled by default (or enabled if remove the negation from the option name, which is generally preferable).

This won't be able to be done using a custom recipe override because as you cannot conditionally override things. Instead, maybe destroy the chest plate and convert it back into diamonds when it is worn.

[DrHenchman]

Will be released in the next version v0.17