feat(nodes): add WithBoard field helper class

This class works the same way as `WithMetadata` - it simply adds a `board` field to the node. The context wrapper function is able to pull the board id from this. This allows image-outputting nodes to get a board field "for free", and have their outputs automatically saved to it.

This is a breaking change for node authors who may have a field called `board`, because it makes `board` a reserved field name. I'll look into how to avoid this - maybe by naming this invoke-managed field `_board` to avoid collisions?

Supporting changes:
- `WithBoard` is added to all image-outputting nodes, giving them the ability to save to board.
- Unused, duplicate `WithMetadata` and `WithWorkflow` classes are deleted from `baseinvocation.py`. The "real" versions are in `fields.py`.
- Remove `LinearUIOutputInvocation`. Now that all nodes that output images also have a `board` field by default, this node is no longer necessary. See comment here for context: https://github.com/invoke-ai/InvokeAI/pull/5491#discussion_r1480760629
- Without `LinearUIOutputInvocation`, the `ImagesInferface.update` method is no longer needed, and removed.

Note: This commit does not bump all node versions. I will ensure that is done correctly before merging the PR of which this commit is a part.

Note: A followup commit will implement the frontend changes to support this change.

invokeai/app/invocations/latent.py

@@ -33,6 +33,7 @@ from invokeai.app.invocations.fields import (
     LatentsField,
     OutputField,
     UIType,
+    WithBoard,
     WithMetadata,
 )
 from invokeai.app.invocations.ip_adapter import IPAdapterField
@@ -762,7 +763,7 @@ class DenoiseLatentsInvocation(BaseInvocation):
     category="latents",
     version="1.2.1",
 )
-class LatentsToImageInvocation(BaseInvocation, WithMetadata):
+class LatentsToImageInvocation(BaseInvocation, WithMetadata, WithBoard):
     """Generates an image from latents."""
 
     latents: LatentsField = InputField(