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

.github/workflows/benchmarking.yml

@@ -133,6 +133,7 @@ jobs:
           --ignore test_runner/performance/test_perf_pgvector_queries.py
           --ignore test_runner/performance/test_logical_replication.py
           --ignore test_runner/performance/test_physical_replication.py
+          --ignore test_runner/performance/test_perf_ingest_using_pgcopydb.py
       env:
         BENCHMARK_CONNSTR: ${{ steps.create-neon-project.outputs.dsn }}
         VIP_VAP_ACCESS_TOKEN: "${{ secrets.VIP_VAP_ACCESS_TOKEN }}"