View plot in editor space

[timtmok]

Add a way to allow a user to view a plot as an editor. This allows a larger view without altering the size of the plots pane and leverages the editor's ability to float as its own window or tile along other editors/plots.

[jmcphers]

Requested (more or less) by beta user: https://github.com/posit-dev/positron-beta/discussions/122

[juliasilge]

I have been doing some prep for teaching a workshop, and I really want this feature.

[jmcphers]

Relevant Mastodon thread:

The only weird thing is no zoom option for plotting.

https://mastodon.online/@rmflight@mastodon.social/112695382560885990

[seeM]

Sort of requested in #3884.

[nstrayer]

I think as long as we have a really good encapsulation of the IPositronPlotClient class it should be relatively straightforward to write an EditorPane/EditorInput class that can act as the front-end.

Work done for #1713 will probably make this easier as it will involve making the front-end as stateless as possible.