This feature is based general.enable_async_metadata setting and works with existing metadata.js file.
The script is compatible with any template:
- the thumbnail div bloc must have attribute
- the bookmark bloc must have attribute with the bookmark ID as value
Fixes#1564
Parameters typing and using strict types overall increase the codebase
quality by enforcing the a given parameter will have the expected type.
It also removes the need to unnecessary unit tests checking methods
behavior with invalid input.
