[WIP] [11.0][ADD] l10n_fi_business_code

[mlaitinen]

Added l10n_fi_business_code module that creates a new field business_id for partners. This field is meant for the Finnish business ID (y-tunnus).

This module requires the partner_identification module from the OCA/partner-contact repository.

[mlaitinen]

@aisopuro @jarmokortetjarvi Wanna review l10n_fi_business_code ported from 10.0 (wasn't in OCA's repo, so I'm not calling a migrated module) to 11.0?

[coveralls]

Coverage remained the same at 54.545% when pulling 92a5f69f7d19aaa26033206e4161f8f4f413b388 on avoinsystems:11.0-business-code into ceab2827b1ed1e56f3a1299ee6ad7115520c292d on OCA:11.0.

[jarmokortetjarvi]

:+1:

[mlaitinen]

I'll create another PR when the 10.0 version of this module has been approved and merged.