Implement basic query for frontend implementation

[nicolas-bastien]

Goal

Provide default behavior for frontenf implementation

Todo

• [ ] repositories get last order by date with a limit
• [ ] post get last publication date
• [ ] Post get previous and next for navigation
• [ ] get category/tag with published post

Missing

Implement db testing to validate each query.

[nicolas-bastien]

@r-ichard do see something missing in this issue ?