Add "cases_analysis" module

[holtgrewe]

Is your feature request related to a problem? Please describe.
We need an implementation of the "Case Analysis" module from the design document.

Describe the solution you'd like
Implement the initial version as cases_analysis. An initial version with minimal functionality and without permissions checks and tests is sufficient at this point so we can generate the API. Also implement permissions and tests.

• add VarFish configuration variable VARFISH_GEN2_ANALYSIS with default 0 to enable the new views
• implement the module, only enable views if VARFISH_GEN2_ANALYSIS is true
• implement permissions and tests
• create follow-up issue for permissions and tests (Finalize cases_analysis module #1736)

Describe alternatives you've considered
N/A

Additional context

• https://varfish-dev-docs.readthedocs.io/en/latest/des_cases_analysis.html