SEO improvements, media and rich text fixes, removed PropTypes

Added

• Structured Data snippets
• Twitter card meta tags

Changed

• Update VSCode settings
• More robust, crossbrowser native video player
• Lazy images start the download of a new image earlier
• Social sharing image for each page, instead of a global one

Removed

• Removed PropTypes eslint validation and any PropTypes in the project, as they are redundant with TypeScript

Fixed

• Disable native scroll restoration
• Custom Rich Text Renderer, with list styles and asset links