Support tuple deconstruction and follow value flows based on index

[KuechA]

• Add functionality to split up the DFG of a statement like (a, b) = ... where the edges are labeled with a new index granularity.
• Add test
• Try with and without brackets
• Use this also in other scenarios (tuples in a return value)
• Special follow DFG functions which have a stack of indices and only select matching tuple elements for unpacking

[codecov]

Codecov Report

Attention: Patch coverage is 83.00654% with 26 lines in your changes missing coverage. Please review.

Project coverage is 77.89%. Comparing base (a5f4ec4) to head (1e2a475).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...kotlin/de/fraunhofer/aisec/cpg/graph/Extensions.kt	77.65%	5 Missing and 16 partials ⚠️
...er/aisec/cpg/passes/ControlFlowSensitiveDFGPass.kt	88.57%	0 Missing and 4 partials ⚠️
...ofer/aisec/cpg/passes/PythonAddDeclarationsPass.kt	92.85%	1 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
...fraunhofer/aisec/cpg/graph/edges/flows/Dataflow.kt	91.48% <100.00%> (+3.11%)	⬆️
...n/kotlin/de/fraunhofer/aisec/cpg/passes/DFGPass.kt	83.69% <100.00%> (+0.45%)	⬆️
...ofer/aisec/cpg/passes/PythonAddDeclarationsPass.kt	90.54% <92.85%> (+1.14%)	⬆️
...er/aisec/cpg/passes/ControlFlowSensitiveDFGPass.kt	80.82% <88.57%> (+0.97%)	⬆️
...kotlin/de/fraunhofer/aisec/cpg/graph/Extensions.kt	59.30% <77.65%> (+4.38%)	⬆️

... and 4 files with indirect coverage changes

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[KuechA]

We cover the basic cases of #1089 but miss some of the tests in #1807, in particular, we do not split up strings into characters nor do we handle the case of the * unpacking operator which seems rather specific to python.

[oxisto]

Looks good in general, minor details needed. We need to have a discussion about our different non-full dataflow types at some point but for now this is the best solution to our problem. Please make the PR title a little more meaningful ;)