Provide filter to convert HTML to markdown

Problem/Motivation

There may be a need to convert HTML to markdown, as markdown may be sometimes preferred for AI prompts more than plain text.
This can be done as feature extension for related issue ✨ Provide filter to convert HTML to plain text Fixed

Steps to reproduce

Proposed resolution

Create filter for this feature to be used within text formats

Remaining tasks

User interface changes

API changes

Data model changes