Tooltips within Emacs for link types

**Is your feature request related to a problem? Please describe.**
Since we cache the Quran lookups ---which we should do for the Bible as well---, it would be nice to show the resulting cached content whenever Emacs users hover over the link.

**Additional context**
Details on how to achieve this task are discussed at
https://alhassy.github.io/org-special-block-extras/#Links