Enhance regeneration of pages during live preview

[jonahtanjz]

Is your request related to a problem?

A follow up to discussions in #1514 and #1529.

When a page is added or removed, all pages are rebuilt if the added/removed file is a page/dependency of page. Similarly, a change in page's properties will cause dependent pages to be rebuilt although this wouldn't affect other pages.

For context:
#1514 (review)
#1514 (comment)
#1529 (comment)

Describe the solution you'd like

1. Only the pages that are dependent on the added/removed pages should be rebuilt.
2. Only the pages which's properties have changed in site.json should be rebuilt. (and even then if using markbind s -o only the page being viewed should be rebuilt)
3. When the attributes in the site configuration (site.json) are modified, only the affected pages should be rebuilt.