feat(userspace): Add banned.h which includes banned functions.

This defines certain functions as invalid tokens, i.e., when
compiled, the compiler throws an error.

Currently only `strcpy` is included as a banned function.

Fixes #788

Signed-off-by: Vaibhav <vrongmeal@gmail.com>

userspace/engine/falco_common.cpp

@@ -18,6 +18,7 @@ limitations under the License.
 
 #include "config_falco_engine.h"
 #include "falco_common.h"
+#include "banned.h"
 
 std::vector<std::string> falco_common::priority_names = {
 	"Emergency",
@@ -117,4 +118,3 @@ void falco_common::add_lua_path(string &path)
 
 	lua_pop(m_ls, 1);
 }
-