Identity propagation

When a rest client interacts with firefly API, it trigger some interaction between firefly core and other components ( e.g. EVM Connect). Currently the context of the originating client is not available to those downstream components. This issue proposes to enhance the internal comms so that components like evmconnect can access context of the originating request ( e.g. jwt claims). This would be very useful, for example, when implementing extensions to the firefly-transaction-manager policy engine.