Enable users to enter Lisk Service URL in network switcher

[reyraa]

Description

Since Lisk Desktop doesn't connect to Lisk Core directly anymore, it doesn't need to receive and save Lisk Core URL. Therefore we should use the custom node input to receive Lisk Service URL.

Motivation

• Enable users to input their favorite Lisk Service API URL.
• Remove the redundant complexity of determining Lisk Service URL from Lisk Core URL.

Acceptance Criteria

• Get rid of getServiceUrl method.
• Get rid of Lisk Core URL in relevant actions, reducers, middleware and React components.
• Input Lsik Service URL from the network switcher input.
• Update Autologin logic to use Lisk Service URL directly.
• Update relevant unit tests