feat: add ITaskManager abstract base class

This class should be the starting point for a class whose
responsibility is going to be dealing with creating all the
Agent related tasks. We aim at supporting both multithreading
and coroutines as our concurrency model, but we allow to swap
coroutines implementations by templating the awaitable type.

Given the current status of the repository this will be momentarily
in the agent folder, but it would be wise to move it to a separate
cmake directory to hide the boost dependency for the implementation
here provided.

src/agent/CMakeLists.txt

@@ -17,6 +17,7 @@ set(SOURCES
 
 set(HEADERS
     include/agent.hpp
+    include/itask_manager.hpp
 )
 
 add_library(agent ${SOURCES} ${HEADERS})

src/agent/include/itask_manager.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <functional>
+
+template<typename CoroutineTaskType>
+class ITaskManager
+{
+public:
+    virtual ~ITaskManager() = default;
+
+    virtual void start(size_t numThreads) = 0;
+    virtual void stop() = 0;
+
+    virtual void enqueueTask(std::function<void()> task) = 0;
+    virtual void enqueueTask(CoroutineTaskType task) = 0;
+};