Illuminated Cloud context menu items should be disabled or work properly on External Libraries node

[Scott Wells]

Nathan Schleifer reports:

"On new projects and maybe all projects, If I right click on External Libraries and choose Illuminated Cloud/ generate offline symbol table nothing happens. It works from a right click on the project name though."

Either the context menu items should be inactive/not present on these nodes or should infer context intelligently based on the Illuminated Cloud module(s) in the project.

[Scott Wells]

Issue tracker grooming.