[FIX] base: incorrect code and locale for Bosnian

Stems from prebiblical commit f083aa2.

Fixes #3480
[IMP] *: one Makefile to rules them all.

Create one unique generic Makefile to compile sass files.
[MERGE] forward port of branch 7.0 up to 65d92da
[MERGE] forward port of branch saas-3 up to d36eee9
[FIX] web,web_kanban: correct radial-gradient usage
[MERGE] forward port of branch 7.0 up to 3e3e35e
[IMP] point_of_sale: add product description and product sale description to the search engine
[FIX] project: missing translations

The labels for fields 'use_tasks', 'partner_id', 'date_start' had no valid string (autogenerated or unrelated).
Make the selections of the field privacy_visibility translatable.
Fixes #3435
[MERGE] forward port of branch saas-3 up to ec27773