70 cleanup repo

[imenelydiaker]

[This PR is a draft]
Done:

• Remove useless mteb files (papers, etc.)
• Some refactoring (code + moved files and folders)

Remaining tasks To Do:

• Move all json files to assets folder
• Rename src folder -> "chroma_embedder", or add the folder inside src (to make it a package, becaue now the package is src)
• Create a folder scripts, and move all scripts there
• Add a docstring/description at the begining of each script
• Update the README (need a section for each script usage)
• Move everything from script_mteb_french to root folder