some maintenance

Added

• npm scripts for easier releasing
• test: html-validate for testing
• code conventions file #76
• test: CodeQL
• Recommended VS Code extensions
• test: Super linter
• build: CI/CD workflows / actions
• renovate for Dependency updates
• feature detection result shown on the demo page
• financial contributors to the README (#82)

Changed

• optimized documentation
• updated devDependencies
• optimized build process
• .gitignore file according to githubs default content
• manifested to use Node 14 for the moment dependening on Webdriver.io
• default branch name from master to main
• replaced dependencies badge