Enable Visibility Panel on a per-page basis

[MadtownLems]

What problem does this address?

The Visibility Panel has a pretty prominent placement in the sidebar, which apparently can't be adjusted yet. (#93)

We'd like to be able to use Block Visibility on one or two pages on sites that contain over a thousand pieces of content. Having that Visibility panel get in the way of every single block on every single piece of content seems like a big "cost" for being to use Block Visibility on a page or two.

What is your proposed solution?

Add an option to the plugin's global settings such as: "Toggle Block Visibility Panel on a per-post basis"
When enabled, there's a checkbox in the Advanced Panel that enables the Visibility Panel for the current Page/Post (instead of showing it for every page/post)

[MadtownLems]

Update: I just realized I can set Block Visibility to only be used for Group Blocks! That's huge for cleaning up the UI, and likely makes this feature request too clunky to be worth it.

Amazing job designing this thing, @ndiego 👏