Add handover

[MalinAhlberg]

Pull Request Template

Description

Basic handover support.
A proof of concept for handovers. See our development beacon for examples.

The available handovers are all set in the config.ini at the moment. If you prefer another type of configuration, we would be happy to discuss it.

Related issues

Fixes #38

Type of change

• 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 not work as expected)
• This change requires a documentation update (this needs a follow up PR)

Changes Made

Testing

• Unit Tests
• Integration Tests
• Tests do not apply
• Needs testing (start an issue or do a follow up PR about it)

Mentions

[teemukataja]

Handovers are an optional feature, and should not be added to the responses always. If drs is configured, this would mean that the handover feature is enabled, and only then should the field be added to the response. If drs in config.ini is empty, don't add these fields.

[blankdots]

address @teemukataja things and we are good to go.

I have an idea how to make this more general and allow multiple types of handovers, but this requires changes to the configuration and it should not be part of this PR.

[blankdots]

Will be followed by a PR for Docs.

[teemukataja]

Commented the drs from config.ini so that the handover-feature is disabled by default on master. To re-enable handover-feature one can uncomment the drs variable from config.ini.