Plugins Manager: Api for adding and removing plugins

[AmmarAbouZor]

On backend we need to provide APIs to add and remove plugins with the following points:

• Add: Add function with the path for the directory of the plugin and the plugin type. This function should validate the directory then copy it to the matching plugins directory in chipmunk home-directory. If the plugin isn't valid it should return an error directly.
• Remove: Function with the path for the plugin directory. This function will return an error if the plugin doesn't exist. Otherwise, it will remove the plugin directory completely.