docs: add report "Move S3 sync script to OVH3"

docs/reports/2024-10-29-move-s3-sync-script-to-ovh3.md

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+# 2024-10-29 Move S3 sync script to OVH3
+
+The script used to synchronize images to AWS S3 (through AWS S3 Open Dataset program) was run on off2 server.
+This server is overloaded (due to I/O), so we now run this script on the OVH3 server (that has a replicate of images through Sanoid snapshots).
+
+OVH3 server has Python 3.7, and the script requires at least Python 3.9. I wanted to install pyenv using the off user, but I didn't manage to get pyenv working with dash, which is the default shell for off user.
+
+As a result, I install [uv](https://docs.astral.sh/uv/) on ovh3 as a replacement, for `off` user:
+
+
+```bash
+curl -LsSf https://astral.sh/uv/install.sh | sh
+```
+
+`uv` is installed automatically in `/home/off/.cargo/bin/uv`.
+
+Install Python 3.11:
+
+```bash
+uv python install 3.11
+```
+
+I moved S3 synchronization script to openfood facts infra repository, in the `scripts` directory ([commit](https://github.com/openfoodfacts/openfoodfacts-infrastructure/commit/42dd4fcdb1f52d55767f33136bc94a6590fa4fd8)).
+
+Note that Python version and dependencies can be directly declared at the top of the Python script, as comment:
+
+```python
+# /// script
+# dependencies = [
+# "openfoodfacts==1.1.5",
+# "orjson==3.10.7",
+# "boto3==1.35.32",
+# "tqdm==4.66.5",
+# ]
+# requires-python = ">=3.9"
+# ///
+```
+
+I also copied the aws credentials in `~/.aws/credentials` on ovh3 server (`off` user).
+
+when launching the script with `uv run sync_s3_images.py`, `uv` automatically creates a virtualenv if needed, install the dependencies and run the script in the virtual environment.
+
+I installed the systemd service and timer on ovh3, and disabled the systemd service/timer on off2 server.