style: added new icons

[markuslindmark]

Describe your changes

Added icons: forward 15, backward 15, analytics
Ran script to create icon font and html example page

Issue ticket number and link

• Fixes #(issue)

Checklist before requesting a review

• [ x] I have performed a self-review of my own code
• [ x] I have verified that the code builds perfectly fine on my local system
• [ x] I have added tests that prove my fix is effective or that my feature works
• [x ] I have commented my code, particularly in hard-to-understand areas
• [x ] I have verified that my code follows the style already available in the repository
• [ x] I have made corresponding changes to the documentation