Fix foal connect react and support build output dir

[LoicPoullain]

Issue

• The command npx foal connect react does not make the react CLI proxify the request to the server anymore.
• When the react application is built, it is not built in the public directory of the Foal server, as is the case for Angular and Vue.

Solution and steps

• Generate environment files to fix this.

Checklist

• Add/update/check docs (code comments and docs/ folder).
• Add/update/check tests.
• Update/check the cli generators.