Add logging to SPA SDKs for crucial configuration and properties

It is observed that more and more SPA implementations encounter issues in the SPA/PMA communication with the main reason the misconfigured or missing properties. Also about functionalities that are being taken care of by our SDKs which however can be influenced by the customer provided configuration and setup.

It would be really helpful for the troubleshooting process if the SDKs would include some logging for crucial properties and configuration for example 

• full request path
• PMA endpoint
• Headers
• etc.

Logging examples

"SPA SDK initialisation. PMA endpoint configured: http://www.example.com/site/resourceapi ...."

"Outgoing request from SPA SDK with request path: ....."

"Provided headers "Authorization":..... "Server-id":....."

This is a follow up from the issue Shutterfly was facing and we had an internal call for it.