[WON'T FIX] Reinstate ability to bookmark action invocations

broken in 1.15.0, and commented out in 1.16.0 to avoid user failures.

The issue is that the BookmarkTreeNode infers a pageType of ACTION_PROMPT, which causes the ActionPromptPage to be rendered. This in turn has a ComponentType of ACTION_PARAMETERS.

However, the ActionParametersPromptPanelFactory explicitly does not match for actions that take no arguments, and so the only component found is UnknownPanel which - of course - fails to add the correct ActionParametersPanel component.

This whole area needs reworking ... the ActionParametersPanel now no-longer supports being invoked with no-args or with populated n-args and automatically resolving to the result of the action invocation.

Instead, will need to move the action execution stuff into the implementation of the AbstractLink that is created within the BookmarkedPagesPanel.

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or: maybe we just keep this functionality commented out; is it used anyway ?