Add more detail to "invalid configuration" exception.

[kober32]

Task specification

Right now, the throwInvalidConfigurationException method throws an exception with the following text:

"Invalid PowerAuthSDK configuration. You must set a valid PowerAuthConfiguration to PowerAuthSDK instance using initializer."

Since this might happen for various reasons, we should add an optional detailed explanation to this error (for example "the configuration is nil") as a parameter to the method mentioned above.

This should also be done for Android