Convert relative URLs to absolute URLs

[hbostan]

Description

For telegram to render <a> tags correctly, href attribute of the tag should be an absolute url. Discrourse, however, sometimes puts relative url to the href attribute causing the text to be rendered as plain text instead of a link.

To fix this, we need to check the links to see if they are absolute links. If they are not, we then should convert them to absolute ones by prepending them with the news.host value from the config.

Relevant Files

newsparser.py