Rework the precision metric. (#9222)

- Rework the precision metric for both CPU and GPU.
- Mention it in the document.
- Cleanup old support code for GPU ranking metric.
- Deterministic GPU implementation.

* Drop support for classification.

* type.

* use batch shape.

* lint.

* cpu build.

* cpu build.

* lint.

* Tests.

* Fix.

* Cleanup error message.

tests/python-gpu/test_gpu_eval_metrics.py

@@ -5,7 +5,7 @@ import pytest
 
 import xgboost
 from xgboost import testing as tm
-from xgboost.testing.metrics import check_quantile_error
+from xgboost.testing.metrics import check_precision_score, check_quantile_error
 
 sys.path.append("tests/python")
 import test_eval_metrics as test_em  # noqa
@@ -59,6 +59,9 @@ class TestGPUEvalMetrics:
     def test_pr_auc_ltr(self):
         self.cpu_test.run_pr_auc_ltr("gpu_hist")
 
+    def test_precision_score(self):
+        check_precision_score("gpu_hist")
+
     @pytest.mark.skipif(**tm.no_sklearn())
     def test_quantile_error(self) -> None:
         check_quantile_error("gpu_hist")