Localize subscription emails

Description

Currently we send emails for different subscription events (recurring charges, invoices, etc...). These emails are English only for the first version due to language preference not being present in the organization. This can be resolved by marking a user account within the organization who wants to receive these emails and then using his language preferences.

Upon further investigation into this issue, the initial idea of adding a subscription manager role might not be ideal because currently we do not allow multiple roles for a single account. Meaning it is not possible to assign someone to manage subscriptions and apps for example unless we make them overlap in a role, which reduces possibility of fine-grained access control.

Following a similar discussion in Pro6pp, we should add a organization locale.