Better implementation to update probe informations

[romain-fontugne]

Currently we update probe information by deleting the json file and recreating it, something like this:

rm cache/probe_info.json; source venv/bin/activate; python3 raclette/tools.py

The issue is that if the tools.py script faces a problem, then we are left with no json file or a corrupted file.

We should:

• Try to get the new data
• Check if the new file can be correctly parsed
• And only if there is no problem with the new file, replace the old file with the new one.