README file under esphome/scripts folder

**Describe the problem you have/What new integration you would like**

The scripts in esphome/scripts are crucial for contributing developers but difficult to understand, I think a README in that folder would be beneficial and could be picked up and autosynched into https://developers.esphome.io/

**Please describe your use case for this integration and alternatives you've tried:**

Have enough understanding of all the esphome/scripts to use them to facilitate development and contributing to ESPHome

**Additional context**

Nice to Have

Review the esphome/scripts folder and the developer documentation at developers.esphome.io to understand the scripts that need coverage and how documentation is synchronized. Done means adding a README under esphome/scripts that gives contributing developers enough context to use the scripts and can be picked up by the documentation site.

Written by the indexing model from the issue text.