Chores
* chore(release): release version 0.20.0 [skip ci] ([`b56961e`](https://github.com/vasilistotskas/grooveshop-django-api/commit/b56961e91927e2f56e7ea7ab2f9954376605697e))
Features
* feat: Search improved, versions bump, minor fixes/improvements.
1) Default db postgres, added DB_PORT new env var, and update name DB_PASS env var to DB_PASSWORD.
2) Country model translations name field max_length change.
3) Order model country and region field on delete set null.
4) populate_country command fixed.
5) Faker and python-semantic-release versions bump.
6) Product fields `discount_value`, `final_price`, `price_save_percent` calculation removed from save method and implement signal and method update_calculated_fields.
7) ProductQuerySet: new methods update_search_vector for search usage and update_calculated_fields.
8) Product Search prototype and tests implemented. ([`bff87a5`](https://github.com/vasilistotskas/grooveshop-django-api/commit/bff87a57d1851cd5b316a3b941ad59d99e067945))