"globalConfig" should be replaced by OSGi configuration

[henrykuijpers]

Currently, the "globalConfig"-node is used to store configuration regarding the usernames/passwords and urls of the AEM instances.

This should be replaced by OSGi configuration, as this is the common way of configuring services in AEM. It also allows easy environment-specific configurations, while the "globalConfig"-way does not.

[bartoszWesolowski]

This will be introduced in: #33