41 add another source of news articles

How many programmers does it take to change a light bulb? None – It’s a hardware problem

Changes:

download_blogs_from_rss.py:
- added ai_blogg and google_ai in LINK_TO_XML_FILE
extract_articles.py:
- modified def extract_articles... to handle non-rss case google_ai blog
- added try/except in def save_articles
datatypes.py
- redefined "description" in BlogInfo as optional

[x] I have checked that I am actually working in the right branch for the purpose of the baglock ticket
[x] I have performed a self-review of my code
[x] I have done a git pull from the remote main branch to make sure there arent any conflicts
[x] I have resolved any eventual conflicts stemming from the point above
[x] I have checked that the naming of my variables, functions, classes are easily understandable
[ ] I have ran a pytest on my test code and everything works as it should
[x] I have added comments to code that will be otherwise be complicated for others
[x] I have checked that my code is properly formatted
[x] I have summarized my changes :point_up:
[x] I have assigned someone else to review my code
[ ] I have fixed all problems that the reviewer found
[x] The CI/CD pipeline is working (Disregard this in the start of the project)