Translate order getCreatedAtFormatted() to store locale

[JeroenVanLeusden]

Description

Extend getDefaultLocale() to allow fetching scoped values. Use this in getCreatedAtFormatted() so created_at date of order will be translated in emails to locale being used in that store view.

Fixed Issues (if relevant)

1. None that I could find.

Manual testing scenarios

1. Set default locale of your store to any language but English.
2. Create order and send confirmation email.

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[okorshenko]

Hi @JeroenVanLeusden thank you for your contributio.

Unfortunately, we can not accept such changes. ReolverInterface has @api tag. In this case we must follow Backward Compatibility Policy

Closing this PR. Feel free submit new PR if you would like to reimplement this following Backward Compatibility Policy