Add support for different model in the same workspace

[johangirod]

## Existing

The LSP will look for all .publicodes files inside the workspace, and consider that they are part of the same model.

Problem

This assumption doesn't stand in the following cases :

• Monorepo with several models
• Workspace with folder of different models opened at the same time

## Solution

Ideally : publicodes models should be delimited by a config file .publicodes.config.ts which contains information for the compiler (extension, files to ignore, strict mode, etc.)

Minimum version : the langage model should use package.json as boundary for model.