Prettier config + vscode settings

Hi,

To simplify sharing code, i would like to propose to reuse the config from the web DAU guys.

Basically:

• Add the .vscode to the project
• Use there version of .prettierrc https://github.com/silx-kit/h5web/blob/main/.prettierrc.json
• Use there version of .editorconfig https://github.com/silx-kit/h5web/blob/main/.editorconfig

This will ensure VSCode is properly configured, and the settings is the same for everybody.

I can take care of the MR