Sending a letter to the author of the article about a new (deleted/updated) comments.

[Dzhonn]

Added the functionality of sending a letter to the author of the article about a new (deleted/updated)
comments. The mail settings are taken from the standard module. Created a separate template for notification emails.

3 files
server\templates\coment.html
server\modules\comments\default\comment.js
server\models\comments.js

I might not send something correctly, this is my first time using GIT.
Please check those 3 files that I have indicated. I will also leave them as attachments here.
mail.zip

[NGPixel]

A few things in your PR that needs to be corrected:

• Do not add content to README.md
• Do not add multiple empty lines in the code
• Do not hardcode strings in the code, especially not in Russian. They can be in English for a PR but ultimately, they should live in Lokalise.
• Your PR is missing several files (e.g. the template). Don't attach them in a zip file, make them part of your PR.
• "coment" should be spelled "comment"

[Gogowitsch]

This PR seems to have overlapping functions with mine at #5778.