feat(user): add myBadges integration

[mpfeil]

Description

This PR introduces user integrations. integrations is a sub-document on the user schema.
The first user integration is myBadges.

Motivation and Context

With the integration of myBadges it is possible to earn different Badges and adds a gamification aspect to the openSenseMap API.

The API is only forwarding some kind of requests to Honeybadgr that is handling the granting process of a badge.

Users who want to participate and earn badges must sign up on https://mybadges.org with the same email address as their openSenseMap user.

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (update dependencies or documentation)

Checklist:

• My code has been linted using yarn run lint.
• My code does not break the tests (yarn run test)
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.