Tooltip library

[mr-islam]

Strings are ready as in #35, just implement something like tippy

• [x] Choose library
• [ ] integrate tippy (or lighter equivalent)
• [ ] customize appearance and speed
• [ ] add option in settings to hide tooltips, but on by default

That last todo is the reason behind using a library — to enable easy toggle of this

[mr-islam]

Tippy looks amazing and worked well in the previous version of Qawl: https://atomiks.github.io/tippyjs/

Use material popover + singleton behavior