Feat: add news analysis

[jameshallam93]

Eventually, I'd like to be able to run analyses on articles from various sources:

• Count number of times a word/phrase is mentioned in each article/source/domain when searching for specific topics
• Analyse left/right/centrist sources for differences in language use
• Check language trends over time (v limited as free API only allows articles up to a month old

To do this, I will need to do the following:

• Set up basic analysis capability (i.e. number of times a word appears in an articles content)
• Expand this to be able to compare across articles
• Expand search system so as to use more than first 20 results
• Run more than 1 query at a time (i.e. one for all fox articles, one for all ABC articles)
• Collate results of analysis of these queries into comparative data
• Expand sourceIds constant to include left/right/centrist bias (add source name whilst doing this for radio button labels)
• Allow searching by political slant (grouping sources together by slant)
• Implement searching by timespan

[jameshallam93]

Having looked closer at the API documentation, I have realised this will have to be much more limited in scope - the article content is truncated to 200 characters, meaning analysis of language used would give very limited information.

I will still look at adding this level of analysis for practice purposes, and will also add ability to see the number of articles that were published including keywords in title on a given date/time period.