Improve base URLs in the documentation

[kober32]

Task specification

In sections describing how to configure the SDK, we often use a random URL, such as https://localhost:8080/demo-server.

We should use something far more likely, like https://my-server-url.com/enrollment-server

For example here: https://developers.wultra.com/components/powerauth-mobile-sdk/1.9.x/documentation/PowerAuth-SDK-for-iOS#configuration

It's both for Android and iOS