[FIX] doc: double period in footer
[FIX] doc: incorrect class access in new api guide

When creating a class with the new API, we should use models.Model
instead of just Model.

closes #3713
[FIX] website_forum: use common method to compute tags for orm
[MERGE] forward port of branch 8.0 up to fc329b6
 [IMP]project : onboarding tips to show what you can get with project and task builder.