Resolve "[FEATURE] Emonio connector"

Summary

Creates a new connection class EmonioConnection that connects Emonio electricity meters to eta_utility.

Explain your context

Emonio meters are used in many applications at ETA Factory. These devices are connectable via numerous protocols. We want to employ them for measuring as well as online optimization applications.

Please list breaking changes, new features or bugfixes

• Breaking changes:

• New features:

  • Adds EmonioConnection class, tests and helpers as well as documentation.

• Bugfixes:

Closes #233 (closed)