Add magnifier annotation tool

[rodrigopedra]

Is your feature request related to a problem? Please describe.

It is not a problem. It is a suggestion for a new annotation tool.

Describe the solution you'd like

I'd like to have a magnifier annotation tool added.

Additional context

There is an app called "Annotator" from elementaryOS' App Center, that has this feature. I use it a lot for tech support.

This app is also developed in github at https://github.com/phase1geo/Annotator/

Below is an screenshot of the tool in action:

Handles description

1. The center where the magnifier is zooming
2. Zoom amount (closer/farther)
3. Magnifier's size

[DamirPorobic]

Looks indeed like a cool feature.