Add optional emission buses to facades

[SabineHaas]

Description

Fixes #165
Adds optional emission buses to facades.

Type of change

Please tick or delete options that are not relevant.

• 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)

Checklist:

Please tick or delete options that are not relevant.

• New and adjusted code is formatted using the pre-commit hooks
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• If new packages are needed, I added them the setup.py
• I have added new features/fixes to the CHANGELOG
• I have added my name to AUTHORS

[SabineHaas]

See #180 and #177