Converting the SLR to as feature and making sure that retry requests are
diverted to the masternode if there is one configured.
Fixes #958 #582

SLR is now a feature

Retries are now diverted to the master node of there is one specified

Cleaning up the folder structure for SLR

Getting rid of the slr test project and moved the tests into the core
instead

Added a new config api to enable/disable features and obsoleted the old
"DisableSecineLevelRetries" method

Setting the SLR retries to 0 now disables the feature

Added a more explicit way to override the SLR retry policy
Improving the logging when handing messages over to SLR.
Closes #1152
Added a acceptance tests to make sure that the SLR works across all
transports