Add a Takeoff class to handle multicopter takeoff

In a deterministic way with clear states to go through.

src/modules/mc_pos_control/Takeoff/TakeoffTest.cpp

@@ -0,0 +1,49 @@
+/****************************************************************************
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+
+#include <gtest/gtest.h>
+#include <Takeoff.hpp>
+
+TEST(TakeoffTest, Initialization)
+{
+	Takeoff takeoff;
+	EXPECT_EQ(takeoff.getTakeoffState(), TakeoffState::disarmed);
+}
+
+// TEST(TakeoffTest, Ramp)
+// {
+// 	Takeoff takeoff;
+// 	takeoff.updateTakeoffState(true, false, true, 1.f, false);
+// 	takeoff.updateThrustRamp(1.f, 0.1f);
+// 	EXPECT_EQ(takeoff.getTakeoffState(), TakeoffState::disarmed);
+// }