Add a global error handler middleware

Create a middlewares folder containing a global errorHandler composant.

Add it in server.js setup file with app.use.

Remove the two useless functions that does a not working similar role in server.js (app.on('error' and .use(function (ctx, next)

This way all error handling can be improved:

• In handlers, replace catch blocks contents with throw error to pass error through to errorHandler.
• Remove all try catch blocks in Services functions.

It will:

• Improve error handling in the API responses
• Improve logging in console
• Improve code readability and reduce code duplication

See what has been done in gatekeeper repository to have a working exemple.