head: improve the metadata exposed
- Improves the metadata exposed, such as site or post description, site or post image. Make use of https://matuzo.at/blog/html-boilerplate/.
- Removes extra empty lines or identation due to badly written layout. However, minifying at build could be a good idea.
- Improves very slightly the webmanifest file.
Co-Authored-by: iGor milhit igor@milhit.ch