[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
[MERGE] forward port of branch 8.0 up to c41109f
[FIX] Add missings files from previous forward port.
[IMP]HR_HOLIDAY:In employee form view in rename Approved Leaves oe_stat button into Leaves to process also add a TO Do filter and rename Number Of Leaves into Remaining Leaves oe_stat button and all group visible by employee ,add a filter type and year. also change a oe_stat button on number of leaves. remove a active= True condtion.