Remove the encoder/decoder dependecy from Hint

src/engine/hint.cpp

@@ -0,0 +1,20 @@
+#include "engine/hint.hpp"
+#include "engine/object_encoder.hpp"
+
+#include <boost/assert.hpp>
+
+namespace osrm
+{
+namespace engine
+{
+std::string Hint::ToBase64() const { return encodeBase64(*this); }
+
+Hint Hint::FromBase64(const std::string &base64Hint)
+{
+    BOOST_ASSERT_MSG(base64Hint.size() == ENCODED_HINT_SIZE, "Hint has invalid size");
+
+    auto decoded = decodeBase64<Hint>(base64Hint);
+    return decoded;
+}
+}
+}