feat(project)!: Remove "put-several" mechanic

[augustebaum]

This is for several reasons:

• it is not as explicit as several simple put calls: the mechanic
  is ambiguous with regards to atomicity (if a key-value pair is
  invalid, does it make the whole operation fail?)
• the mechanic makes it complicated to add options to put,
  e.g. the note option proposed in
  Annotate the version of an item #1041
  or the display_as option proposed in
  feat: As a user, i want to retrieve a CrossValidationReporter from a project #1045 (comment).

[github-actions]

Coverage Report for backend

File	Stmts	Miss	Cover	Missing
venv/lib/python3.12/site-packages/skore
__init__.py	12	0	100%
__main__.py	8	1	80%	19
exceptions.py	3	0	100%
venv/lib/python3.12/site-packages/skore/cli
__init__.py	5	0	100%
cli.py	33	3	85%	104, 111, 117
color_format.py	43	3	90%	35–>40, 41–43
launch_dashboard.py	26	15	39%	36–57
quickstart_command.py	14	7	50%	37–51
venv/lib/python3.12/site-packages/skore/item
__init__.py	21	1	91%	46
cross_validation_item.py	137	10	93%	27–42, 370
item.py	41	13	68%	85, 88, 92–112
item_repository.py	42	2	93%	12–13
media_item.py	70	4	94%	15–18
numpy_array_item.py	25	1	93%	15
pandas_dataframe_item.py	34	1	95%	15
pandas_series_item.py	34	1	95%	15
polars_dataframe_item.py	32	1	94%	15
polars_series_item.py	27	1	94%	15
primitive_item.py	27	2	92%	13–15
sklearn_base_estimator_item.py	33	1	95%	15
skrub_table_report_item.py	10	1	86%	11
venv/lib/python3.12/site-packages/skore/persistence
__init__.py	0	0	100%
abstract_storage.py	22	1	95%	130
disk_cache_storage.py	33	1	95%	44
in_memory_storage.py	20	0	100%
venv/lib/python3.12/site-packages/skore/project
__init__.py	3	0	100%
create.py	52	8	88%	116–122, 132–133, 140–141
load.py	23	3	89%	43–45
open.py	14	0	100%
project.py	57	3	92%	109, 143, 147
venv/lib/python3.12/site-packages/skore/sklearn
__init__.py	4	0	100%
_base.py	141	2	98%	168–>173, 184–185
find_ml_task.py	35	1	95%	41–>49, 50
types.py	2	0	100%
venv/lib/python3.12/site-packages/skore/sklearn/_estimator
__init__.py	10	0	100%
metrics_accessor.py	198	2	98%	131, 267
report.py	109	0	98%	160–>166, 168–>170
utils.py	11	11	0%	1–19
venv/lib/python3.12/site-packages/skore/sklearn/_plot
__init__.py	4	0	100%
precision_recall_curve.py	126	2	97%	200–>203, 313–314
prediction_error.py	75	0	99%	289–>297
roc_curve.py	95	3	94%	156, 167–>170, 223–224
utils.py	77	0	100%
venv/lib/python3.12/site-packages/skore/sklearn/cross_validation
__init__.py	2	0	100%
cross_validation_helpers.py	47	4	90%	104–>136, 123–126
cross_validation_reporter.py	35	1	95%	177
venv/lib/python3.12/site-packages/skore/sklearn/cross_validation/plots
__init__.py	0	0	100%
compare_scores_plot.py	29	1	92%	10, 45–>48
timing_plot.py	29	1	94%	10
venv/lib/python3.12/site-packages/skore/sklearn/train_test_split
__init__.py	0	0	100%
train_test_split.py	36	2	94%	16–17
venv/lib/python3.12/site-packages/skore/sklearn/train_test_split/warning
__init__.py	8	0	100%
high_class_imbalance_too_few_examples_warning.py	17	3	78%	16–18, 80
high_class_imbalance_warning.py	18	2	88%	16–18
random_state_unset_warning.py	11	1	87%	15
shuffle_true_warning.py	9	0	91%	44–>exit
stratify_is_set_warning.py	11	1	87%	15
time_based_column_warning.py	22	1	89%	17, 69–>exit
train_test_split_warning.py	5	1	80%	21
venv/lib/python3.12/site-packages/skore/ui
__init__.py	0	0	100%
app.py	25	5	71%	24, 53–58
dependencies.py	7	1	86%	12
project_routes.py	50	0	100%
venv/lib/python3.12/site-packages/skore/utils
__init__.py	0	0	100%
_accessor.py	7	0	100%
_logger.py	21	4	84%	14–18
_show_versions.py	31	0	100%
venv/lib/python3.12/site-packages/skore/view
__init__.py	0	0	100%
view.py	5	0	100%
view_repository.py	16	2	83%	8–9
TOTAL	2229	135	93%

Tests	Skipped	Failures	Errors	Time
398	0 💤	0 ❌	0 🔥	45.333s ⏱️

[thomass-dev]

Nice, thanks!