[Outline] Add support for left or right positioned Outline

[staghouse]

Is your feature request related to a problem? Please describe.

I would like to move the Outline to the left of the main content which can be done relatively easily with CSS however the caveat is because when we use frontmatter to hide the outline on certain pages it creates a gap on the left side instead of completely hiding the Outline’s parent container.

Describe the solution you'd like

Two things:

1. Theme Config to have something like “outlinePosition” that takes “left” or defaults to “right” and positions the outline correctly.
2. Change the logic so that when frontmatter has outline set to hidden for a page that the entire Outline element is removed instead of it’s child elements which will prevent the left aligned Outline from creating a left side gap.

Describe alternatives you've considered

Using CSS to move the Outline element but it not fully work with frontmatter setting an outline to false on a specific page by creating an empty gap because the parent element of Outline is not removed.

Additional context

No response

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