finalize SASL, move all IRC-related includes to a specific folder

include/base64.h

@@ -0,0 +1,9 @@
+#ifndef BASE64_H
+#define BASE64_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+int base64_encode(const uint8_t *in, size_t in_len, char *out, size_t out_size);
+
+#endif