AM-326 ams:Introduce trace id identifier in logs

[agelostsal]

Added a new parameter that should be present in all logs that take place after a user has executed any request against the system.
The trace_id parameter will assist in grouping logs of the same originator making it easier to check what happened during a specific flow.

The most idiomatic way to add request-scoped parameters is through the standard context package.
It's common in go to propagate context as a first parameter in each function.

The biggest change is the store interface which had all its methods to accept a context as first argument.
This change also helps in the migration to the new mongo official driver, which expects context on all its calls.