View text files that are not UTF-8 encoded

[plbstl]

Description

This PR allows CodeEdit to show file contents in a different encoding from utf8.

The files in the related issues show up. I don't know how accurately, but it does a good job.

NOTE: Files are still saved using UTF8 encoding.

Related Issues

• Fixes 🐞 Cannot show the contents of text files that are not UTF-8 encoded #1726
• Fixes 🐞 Opening a text file with non standard encoding appears empty #1263

Checklist

• I read and understood the contributing guide as well as the code of conduct
• The issues this PR addresses are related to each other
• My changes generate no new warnings
• My code builds and runs on my machine
• My changes are all related to the related issue above
• I documented my code

Screenshots

BEFORE:

cannot.view.text.files.that.are.not.UTF8.encoded.mov

AFTER:

view.text.files.that.are.not.UTF8.encoded.mov

[activcoding]

LGTM