Osw

- add database controller

Version v0.5.x

- Implemented an alternative cast method discriminating None values
- fix large cookie error after > 100 edits
- add support to store a list of entities
- encoding fixes

- fix datamodel-code-generator version to 0.15.0

- use editslots API
- remove None entries in json exports
- set default content for header and footer slot
- improve docs
- update examples

- add local slot edit feature

- rename OSL to OSW
- add page package feature

- create package