Added a new category for Asia

[chunshek]

I added a new category for Asia, with 226 English-language feeds that cover news and analysis for:

• Asia (region-wide, both international and domestic outlets)
• East Asia: China, Hong Kong, Japan, Korea, Macao, Mongolia, Taiwan
• Southeast Asia: Brunei Darussalam, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, Timor-Leste, Vietnam
• South Asia: Bangladesh, Bhutan, India, Nepal, Maldives, Pakistan, Sri Lanka

There are multilingual display names for the feed, including official languages for all of the above places.

[chunshek]

@vprelovac @giorgiobrullo
While making changes for #366, I noticed there is also a very small "Asia" category in core_feeds.py which is not currently shown. Would that impact this PR?

[giorgiobrullo]

@vprelovac @giorgiobrullo While making changes for #366, I noticed there is also a very small "Asia" category in core_feeds.py which is not currently shown. Would that impact this PR?

It would not, will remove it because it's unused.

Thank you for your work! This is great.