[QOL]: Add a clone feature for plugins

[gynt]

• We needed this functionality a lot: the ability to clone an existing plugin.
• The cloning process should include automatic renaming (like giving it the dialog for creating a new plugin but based on an existing one without adding it as a dependency).
• This is useful for plugins that don't want to depend on other plugins that might be similar, then remove a bunch of their dependencies and instead use a similar configuration but with different dependencies.
• E.g., if you want to make something based on UCP2 legacy but don't want to redo tons of configurations:
  • Take the vanilla retraced plugin as a base.
  • Keep the UCP configuration part of it, and maybe the maps because you like them.
  • Then switch out a bunch of other stuff.
• This means you don't need to start building the dependency and configuration list from scratch, and you can rely on how the files were set up (ini.lua for textures).

#220

[gynt]

I think I need to see a more specific use case first. What is the goal when using the clone feature? Do you mean the newly cloned plugin has the original plugin as a dependency?