Add a script to generate mock data

In order to do more more thorough tests on geovisio, especially on the performances, feeding it with arbitrary data can be handy.

This adds a flask target to generate and import a set of sequences. For the moment a base image is needed to be duplicated with update exif metadata (so taking a small image can be better for some tests).

It can be run with:

FLASK_APP="src" flask  fill-mock-data --base-image-path=<path to an image.jpg> --max-size=10_000_000_000 --nb-sequences=10

In the future we might improve this:

• with different images used
• with more realistic sequences. A projection of some roads would be better 🗡

Caption of the loaded data:

Note: I'm not sure if this needs to be a flask target or if it should be completely separated. Feel free to tell me if you want better separation.