Moved publishmessage method into separate file.

ie changing names of interfaces and moving structs to other files. Also
gitignore updated to ignore the 'make coverage' outputs.

An error message now gets published if there is an error while
converting the query or there is a database error.

Mainly testing the handlemessage method with different input messages.

Implements the ConvertQuery method and just returns a hardcoded string
value.

Updated integration test

Updated database credentials to kubernetes Arangodb credentials.

Added comments for go linting

Also updated Makefile and deployment file.