Save empty content when text editor is fully cleared

[spaenleh]

Problem:

When all the text from the quill editor is removed, the saved content of the document is not '' but <p><br></p>.

So when rendered it will occupy a non-null space.

Solutions:

1. Strip the content before saving, to save an empty string instead of a breakline
2. Save as is but check for "empty line content" when rendering the text