Major refactor including switch to pymediawiki

[krisgesling]

Description

In the search for better images it was clear that the existing wikipedia python package being used was abandonware. pymediawiki is one of the projects that came out of it and provides a lot of the same functionality but with quite a different wrapper.

This PR extends on #69 though primarily replaces it:

• switches the Skill to interface with Wikipedia using pymediawiki
• refactor Skill to reduce duplication and use consistent terms throughout
  • title is a str representing the name of a page
  • page is an instance of the MediaWikiPage object
  • Article is a combination of data for a page, that isn't all available on the page object
• fetches page thumbnail image directly from Wikipedia API for speed and flexibility
• fetches images for CQS in parallel to providing the answer back to CQS - this vastly speeds up response times eg 8s > 3s
• MOAR DOCSTRINGZ

Future work

• [ ] Improve disambiguation handling - currently disabled - will just report the most likely answer
• [ ] Sync GUI display time with reading of summary - waiting for Skills Interaction sprint
• [ ] Improve VK tests - should be switched over to the new MessageWaiter functions when they're available in stable.

Type of PR

• [x] Bugfix
• [x] Feature implementation
• [x] Refactor of code (without functional changes)
• [x] Documentation improvements
• [x] Test improvements

Testing

VK tests

Documentation

Docstrings added all round

CLA

• [x] Yes

[krisgesling]

Caught another bug while I was testing these changes.

Disambiguation results can refer to other disambiguation pages :loop:

This was raising a DisambiguationError for some queries. So the new function recursively processes disambiguation results to fetch a valid page that is a likely strong result to the original query. It also refers back to the original or "top-level" disambiguation page title as this would best reflect the users question.