Fix escaped markdown not being cleaned up for HTML and ODT

[vkbo]

Summary:

This PR changes how escaped markdown characters are handled. Previously, they were handled in a post processing step that only actually worked for the document viewer.

The new implementation runs a utility function on each piece of text that goes into an HTML or ODT paragraph during the processing loop. This is now format-dependant and the post processing function itself has been removed.

Related Issue(s):

Closes #1412

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