[Extensibility] Use package.json in twenty application instead of twenty-app.jsonc

[martmull]

Will permit to add node dependancies for serverless function an compute lambda layer easily

• add a package.json at the root of the application, and add some more fields like standardId like raycast does ( see https://github.com/raycast/extensions/blob/main/extensions/asana/package.json). Thanks to that we will provide proper packages to serverless functions