Add TelegramRenderer || красивый контент в телеге

[Bobronium]

Motivation

I was going to just add URLs to telegram images, so it would be possible to view new memes without loading the whole comments section...

However this quickly turned into a quest of implementing support for rendering markdown posts for TG.

Markdown

1. Учишь английский
	- ![Oi mate...](https://i.imgflip.com/705kt7.jpg)
3. ~~Ду...~~ Учишь Питон
	```python
	print("Hello, Vas3k!")
	```
3. Едешь в Германию работать
	- [HowToBerlin](https://howtoberlin.de/)

Before	After

Changes

• Replaced PlainRenderer with TelegramRenderer to support Telegram formatting
• Replaced render_plain with render_tg that now passes through HTML tags
• Updated render_plain to render_tg across all telegram messages templates
• Don't wrap intro in a code block (for moderators)

Upd. Left render_plain and PlainRenderer in place for future use

[vas3k]

Не удаляй render_plain, он еще пригодится не только для телеграма

[Bobronium]

@vas3k, вернул на место

[vas3k]

Ну вот так получше. Можем потестить, если будет херово — я откачу обратно на plain