Inform user when Baud Maybe wrong

Summary:

• Add new atcoreMessage on connection saying what plunin was loaded
• Abort connection attempts taking longer then 20 seconds. Inform the user to check settings and retry.

Test Plan: Open test client try to connect with wrong baud. Wait 20 Seconds View message.

Reviewers: patrickelectric, tcanabrava, laysrodrigues

Reviewed By: tcanabrava, laysrodrigues

Subscribers: yurchor, Atelier: AtCore

Tags: Atelier: AtCore

Differential Revision: https://phabricator.kde.org/D17889