COHIV-202: Refactor NK report code

[MarcoSteinacher]

The goal is to split the legacy code in report/nk_report.py into multiple files and classes in report/nk/.

Currently, only the simple cost type NkTotalCost is implemented and some tests. Refactoring of other cost types will follow.

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[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
django/geno
api_views.py
models.py					743, 745, 748-749, 751
utils.py					212, 221
django/geno/tests
data.py
django/report
generator.py					26, 32
report_nk.py					2904
tasks.py					29-35
django/report/nk
bill.py					80, 119, 126-127, 131-132, 158, 192-198, 217, 250, 267, 290-293, 300-320, 368-372, 385, 407-410, 432
contract.py					16, 45, 55, 111-112, 118
cost_config.py
export_csv.py					73, 77, 100, 122-126, 136-137, 167, 171, 177, 184-189, 193, 199-204, 208, 239, 243, 252, 256, 281-282, 286, 294
generator.py					215-220, 240, 244, 246, 261, 271, 275, 282-286, 315, 317, 346, 351-355, 390, 398, 400, 450-453, 458-477, 479, 482-485, 491, 516, 530, 533-537, 547, 562, 604-608, 612, 621, 627, 630-633, 639-648, 651-656, 661-663
graph.py					23-93, 96-245, 250-254, 263-273, 284-542
rental_unit.py					38, 41-44, 51-53, 56-58, 96, 103, 105, 116, 122, 139
section.py					22
django/report/nk/cost
__init__.py
base.py					60, 81, 89-90, 101, 103, 130, 137, 194
general.py					20-23, 57-61
django/report/tests
base.py
test_nk_bill.py					227
test_nk_contract.py					19
test_nk_cost.py
test_nk_generator.py
test_nk_report.py
django/reservation/tests
test_models.py
Project Total

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