Replaced all SVG icons by TTF font

[veler]

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• UI change (please include screenshot!)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Internationalization and localization
• Other (please describe):

What is the current behavior?

In DevToys, a good part of the tools icons come from SVG files shipped with the app.
These SVG files are loaded asynchronously. The theme is applied to the SVG, then it's being loaded by the UI engine, then when the size is applied, we scale it by.... reloading it with the size we know about...

This is:

1. EXPENSIVE. That's why DevToys takes up to 1 second to display all the icons on a slow machine.
2. NOT-MEMORY-FRIENDLY. This is the root cause of Memory leak in SearchResults #369.

Issue Number: #369, #416

What is the new behavior?

Replaced all the SVG by a TTF font.

Other information

BEFORE

AFTER

Quality check

Before creating this PR, have you:

• Followed the code style guideline as described in CONTRIBUTING.md
• Verified that the change work in Release build configuration
• Checked all unit tests pass