Added fake node context

[RunDevelopment]

This adds a new context FakeNodeContext that informs other components/hooks whether the current node is fake. We have several features that need to know whether the current node is fake:

• Refactoring options need to know this, because they create a real node and connect it to a fake node otherwise.
• Copy Override ID assumes that the node is real. The override ID of a fake node doesn't make sense anyway.
• Handles need to be swapped out for fake handles. (This was implemented already.)
• The view image (eye) button on image outputs create a new node.

The new context makes it easy for all of them to know whether the current node is fake and change their behavior accordingly.

This is important for when we make fake nodes interactive (soon).

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Changes:

• Added FakeNodeContext and used it everywhere.
• Moved CopyOverrideIdSection into refactoring options. Not quite a refactoring option, but close.
• Make the view image (eye) button do nothing in fake nodes.