merge v0.2.0 to master

Added

• PostgreSQL support (#30 (closed))
• Brave Browser and Brave Browser's Private Windows with Tor as new fetchers (#37 (closed))
• Force quitting chromedriver and Chromium if it doesn't gracefully quit

Changed

• Updated README file to match this version
• Updated Dockerfile and Docker Compose file to make them work again (#28 (closed))

Removed

• SQLite support