This allows two different classes in different modules to be refactored
to the same name - for example, Node in client and unpackclass.
Under the hood, it is implemented by prefixing each class name with the
library name and an exclamation mark (which is highly unlikely to appear
in a class name, as it is invalid Java syntax).
At first, prefixing class names with the library name feels like a bit
of a hack. However, it is much simpler than trying to track libraries
throughout the existing code. Furthermore, it allows us to avoid
forking ASM classes like Remapper.
The Fernflower driver was also changed to deobfuscate each library in
its own context, rather than trying to decompile them all in one go - by
the time classes reach Fernflower, the prefixes have already been
removed and Fernflower can't deal with duplicate class names either.
Signed-off-by: Graham <gpe@openrs2.dev>