fix: Save listener duration as milliseconds

[taorepoara]

About this PR

The listener duration is saved as seconds so it's mostly 1 or 0 depending on the app.

This is now changed to milliseconds.

Technical highlight/advice

I also changed the log pattern to have time informations.

How to test my changes

• Create an app (could be locally with the doc that I added)
• Run the app
• Look at the session measurement tables

Checklist

• I didn't over-scope my PR
• My PR title matches the commit convention
• I did not include breaking changes
• I made my own code-review before requesting one

I included unit tests that cover my changes

• 👍 yes
• 🙅 no, because they aren't needed
• 🙋 no, because I need help

I added/updated the documentation about my changes

• 📜 README.md
• 📕 docs/*.md
• 📓 docs.lenra.io
• 🙅 no documentation needed