Add Url recognition and formatting

[vkbo]

Summary:

This PR adds support for highlighting and formatting URLs pasted into the document. These are also clickable in the viewer, can be followed with the context menu in the editor, and export correctly to rich text document formats.

Related Issue(s):

Closes #1426

Reviewer's Checklist:

• The header of all files contain a reference to the repository license
• The overall test coverage is increased or remains the same as before
• All tests are passing
• All flake8 checks are passing and the style guide is followed
• Documentation (as docstrings) is complete and understandable
• Only files that have been actively changed are committed