WIP: Add modules donated by Atruvia AG

[robin-checkmk]

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Issue Number: #646

What is the new behavior?

• Add module for DCD
• Add modules for BI
• Extend authentication

Other information

We would like to thank Atruvia AG for their gratious code donation!
Their willingness to share their internal code with us served as a basis for the content added with this PR.
Thanks a lot!
(does not seem to have the customer attribute)

ToDo

• Make modules Python 2.7 and 3.5 (see failing sanity tests)
• Double-check docs
• Create integration tests for all modules
  • bi_pack
  • bi_rule
  • bi_aggregation
  • dcd
  • Enable all Sites for integration tests
• Make modules 2.4.0-ready
  • bi_pack
  • bi_rule
  • bi_aggregation
  • dcd
• Make modules CME-ready
  • bi_pack (does not seem to have the customer attribute)
  • bi_rule (does not seem to have the customer attribute)
  • bi_aggregation
  • dcd
• bi_rule module:
  • params is required by the REST API this makes no sense, but will also not be fixed soon, so we need either a workaround or documentation
• Check if differ.py can be moved into utils.py.
• Check if ExtendedCheckmkAPI can become part of CheckmkAPI (in apy.py).
• Check copyright headers and CODEOWNERS
• Discuss new auth mechanisms
• Add tests (unit/integration?) for new auth mechanisms