Move logic for ingest benchmark from GitHub workflow into python testcase (#9762)

## Problem

The first version of the ingest benchmark had some parsing and reporting
logic in shell script inside GitHub workflow.
it is better to move that logic into a python testcase so that we can
also run it locally.

## Summary of changes

- Create new python testcase
- invoke pgcopydb inside python test case
- move the following logic into python testcase
  - determine backpressure
  - invoke pgcopydb and report its progress
  - parse pgcopydb log and extract metrics
  - insert metrics into perf test database
 
- add additional column to perf test database that can receive endpoint
ID used for pgcopydb run to have it available in grafana dashboard when
retrieving other metrics for an endpoint

## Example run


https://github.com/neondatabase/neon/actions/runs/11860622170/job/33056264386

test_runner/fixtures/benchmark_fixture.py

@@ -256,12 +256,17 @@ class NeonBenchmarker:
         metric_value: float,
         unit: str,
         report: MetricReport,
+        labels: Optional[
+            dict[str, str]
+        ] = None,  # use this to associate additional key/value pairs in json format for associated Neon object IDs like project ID with the metric
     ):
         """
         Record a benchmark result.
         """
         # just to namespace the value
         name = f"{self.PROPERTY_PREFIX}_{metric_name}"
+        if labels is None:
+            labels = {}
         self.property_recorder(
             name,
             {
@@ -269,6 +274,7 @@ class NeonBenchmarker:
                 "value": metric_value,
                 "unit": unit,
                 "report": report,
+                "labels": labels,
             },
         )