Refactor callback mechanism

Problem/Motivation

Since v0.7.10 klaro has own callback functions onAccept, onDecline and onInit. We need this callbacks for Google Consent Mode v2.

Proposed resolution

Add these options to Klaro Apps.

Remaining tasks

• Create options and change Klaro App Form
• Mark the existing hook as deprecated (the current callback was called on every change, so we cannot move the existing callback to the new onAccept, onDecline

User interface changes

Settingsform for Klaro Apps.

Data model changes

Config for Klaro Apps.