feat(ipc): New ipc module

Add a new module that allow users to configure hooks
on received ipc messages. The hook will execute the defined
shell script and the output of the script will be used
as the module content.

Ref #84

include/utils/command.hpp

@@ -80,4 +80,7 @@ namespace command_util {
   }
 }
 
+using command = command_util::command;
+using command_t = command_util::command_t;
+
 LEMONBUDDY_NS_END