[schema] store default attribute values in a Bytes field, allowing python objects as default values
Notes:
* Binary objects grow two methods
* we depend on a newer yams version
* the code is quite simplified as a result of the whole change
* a very old and nasty bug where bool(default values) evaluating to
False not being properly migrated is killed
Closes #2414591.
CSS Coding Standards--------------------(Draft, to be continued):Naming: camelCaseIndentation rules~~~~~~~~~~~~~~~~~- 2 espaces avant les propriétés- pas d'espace avant les ":", un espace après- 1 seul espace entre les différentes valeurs pour une même propriétéDocumentation~~~~~~~~~~~~~Please keep rules semantically linked grouped together, with a comment aboutwhat they are for.Recommendation~~~~~~~~~~~~~~- Try to use existing classes rather than introduce new ones- Keep things as simple as possible while in the framework- Think about later customization by application- Avoid introducing a new CSS file for a few lines of CSS, at least while the framework doesn't include packing functionalities