TECHNICAL: add minimal validation testing

[stijn-dejongh]

Improve the deployment pipeline by adding in:

• MarkDown syntax checks and style linting
• Deployment checks using testing library
  • validate all links work
  • verify all tags have a page with relevant content
  • verify all books have a dedicated page
• Automated grammar and spelling checks ( if possible )

[stijn-dejongh]

Notes and Options

Validity checks

• @Vankerkom has recommended the use of MS PlayWright to create the content validation.
• An alternative is to use a regular JEST harnass, or go all out using a Selenium based implementation

Linting and Grammar check

• Consider using OpenAI (or derivative) public API's to check the raw content
• Alternative spellchecker could be something like CodeSpell
• Linting can be done using MarkdownLint