Text width

[vkbo]

Summary:

Remove the switch to enable/disable fixed text width in editor and instead allow the user to set the value to 0 to disable it. Also apply the max width setting to the document viewer.

Related Issue(s):

Resolves #924

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