Improve editor auto-replace

[vkbo]

Summary:

This PR moves auto-replace into its own class. The new implementation is likely a minor improvement in the cases were only some auto-replace features are enabled, and should perform about the same in cases where many or all are in use. Mainly, it is just a refactoring to separate it from the main editor code and move all its associated class attributes.

Related Issue(s):

Related to #2129

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