Refactor CMakeLists.txt OpenSSL handling

First, we do not include openssl globally using `include_directories()`,
as most modules don't need it. Further, it is linked into SECURITY, and
removed from all other targets (they don't need it, only SECURITY).

Finally, remove a header include in NR PDCP that is not needed

openair2/LAYER2/nr_pdcp/nr_pdcp_integrity_nia1.c

@@ -24,7 +24,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdint.h>
-#include <openssl/cmac.h>
 
 #include "openair3/SECU/secu_defs.h"
 #include "openair3/SECU/key_nas_deriver.h"