Feature: Quality estimation provider articles

[bittlingmayer]

Request: Articles for each quality estimation provider, generated from data

Additional context:

We should structure this similar to how we do APIs, integrations and aggregators.

• _data/quality-estimation.json
• generate.py
• _layout/quality_estimation.html
• Include the list in the main article
• Move the main article to the top level in the sidebar, e.g. under Languages

[bittlingmayer]

@tovmasharrison