Develop Volto add-ons

• Install an add-on in Volto
• Install an add-on in development mode in Volto 18
• Install an add-on in development mode in Volto 17
• Load configuration from add-ons
• Create an add-on for Volto 18
• Create an add-on for Volto 17
• Test add-ons in Volto 18
• Test add-ons in Volto 17
• Extend webpack setup from an add-on
• Extend ESLint configuration from an add-on
• Troubleshoot untranspiled add-on dependencies
• Add-on internationalization
• Best practices for add-ons
• Create a Volto theme add-on
• Add static files from your add-on to your build