Move benchmark download tool and visualization to the CI (#9075)

Creates a new [Benchmarks upload](https://github.com/enso-org/enso/pull/9075/files#diff-8859b4f24c2f25d300fe800ee431d7f9f7e68de459395a7e9b22abf79440c862) GitHub action that fetches all the latest benchmark results, and uploads them on the website hosted on https://github.com/enso-org/engine-benchmark-results repo. The results are stored in that repo in a bunch of JSON files.

# Important Notes
The new *Benchmarks upload* action is scheduled to run after either "Engine benchmarks" or "Standard library benchmarks" jobs are complete.

.github/workflows/bench-upload.yml

@@ -0,0 +1,46 @@
+# This file is manually managed. It is used to upload benchmarks to to the
+# https://github.com/enso-org/engine-benchmark-results repository.
+
+name: Benchmarks upload
+on:
+  workflow_run:
+    workflows: ["Benchmark Engine", "Benchmark Standard Libraries"]
+    types:
+      - completed
+jobs:
+  upload-benchmarks:
+    name: Upload benchmarks
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout enso repository
+        uses: actions/checkout@v4
+        with:
+          repository: enso-org/enso
+          path: enso
+      - name: Checkout engine-benchmark-results repository
+        uses: actions/checkout@v4
+        with:
+          repository: enso-org/engine-benchmark-results
+          path: engine-benchmark-results
+          token: ${{ secrets.ENSO_BENCHMARK_RESULTS_TOKEN }}
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y \
+            python3 \
+            python3-jinja2 \
+            python3-numpy \
+            python3-pandas
+          sudo apt-get install -y gh
+      - name: Set up git
+        run: |
+          git config --global user.email "[email protected]"
+          git config --global user.name "Enso CI Bot"
+      - name: Upload benchmarks
+        run: |
+          cd enso/tools/performance/engine-benchmarks
+          python3 website_regen.py \
+            -v \
+            --local-repo  ${{ github.workspace }}/engine-benchmark-results
+        env:
+          GITHUB_TOKEN: ${{ secrets.ENSO_BENCHMARK_RESULTS_TOKEN }}

tools/performance/engine-benchmarks/README.md

@@ -4,6 +4,12 @@ This directory contains a python script `bench_download.py` for downloading
 Engine and stdlib benchmark results from GitHub, and `Engine_Benchs` Enso
 project for analysing the downloaded data.
 
+Note that for convenience, there is `bench_tool` directory that is a Python
+package. The `bench_download.py` script uses this package.
+
+To run all the Python tests for that package, run `python -m unittest` in this
+directory.
+
 Dependencies for `bench_download.py`:
 
 - python >= 3.7