Separate prerequisites and configuration in the readme

Change-Id: I31c7c86a0f9da8e4a144cadc8959caefc53969fb
Reword the prerequisites in the readme

Change-Id: Ia7cb549ccb2453e984596514aba737a54155a0b9
Document the HTTP password configuration for REST API usage

Change-Id: I2a9d0e50978334e560e076791029746f2531ea51