Revert removing of php7.0-mbstring and php7.1-mbstring

[willy-ahva]

Description

There was a bug on the PIM: mb_string was used somewhere on the PIM but not required. So people install without mb_string and had a bug. What was did is to remove the use of mb_string in the PIM and remove the extension from docker/ansible.

But it seems that behat need mb_string.

[2.3 ?]$ docker-compose exec fpm composer install --prefer-dist

Loading composer repositories with package information Updating dependencies (including require-dev) Your requirements could not be resolved to an installable set of packages.

Problem 1

• Installation request for behat/behat 3.4.3 -> satisfiable by behat/behat[v3.4.3].
• behat/behat v3.4.3 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. Problem 2
• Installation request for phpunit/phpunit 6.5.3 -> satisfiable by phpunit/phpunit[6.5.3].
• phpunit/phpunit 6.5.3 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system. Problem 3
• behat/behat v3.4.3 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
• sensiolabs/behat-page-object-extension v2.1.0 requires behat/behat ^3.0.6 -> satisfiable by behat/behat[v3.4.3].
• Installation request for sensiolabs/behat-page-object-extension 2.1.0 -> satisfiable by sensiolabs/behat-page-object-extension[v2.1.0].

Definition Of Done

Q	A
Added tests	Todo
Changelog updated	Todo
Documentation	-
Fixed tickets	#...

Todo: Pending / Work in progress OK: Done / Validated -: Not needed

[AymericPlanche]

:-1: mbstring is not an extension required by the pim, it doesn't have to be in the docker image.

see https://akeneo.atlassian.net/browse/PIM-7903

and

https://akeneo.slack.com/archives/CAT7MQP9D/p1543920319019700

EDIT: didn't read the description, ok for behat...