Move hashtable to ds/ folder

Notably, remove the include_directories(), which is not necessary, as
most files do not actually use this.

openair2/F1AP/CMakeLists.txt

@@ -3,7 +3,7 @@ add_subdirectory(MESSAGES)
 
 if(ENABLE_TESTS)
   add_executable(f1ap_ids_test f1ap_ids_test.c f1ap_ids.c)
-  target_link_libraries(f1ap_ids_test HASHTABLE minimal_lib)
+  target_link_libraries(f1ap_ids_test ds minimal_lib)
   add_dependencies(tests f1ap_ids_test)
   add_test(NAME F1AP_ID_test COMMAND f1ap_ids_test)
 

openair2/F1AP/f1ap_ids.c

@@ -25,7 +25,7 @@
 #include "f1ap_ids.h"
 
 #include <pthread.h>
-#include "common/utils/hashtable/hashtable.h"
+#include "ds/hashtable.h"
 #include "common/utils/assertions.h"