global: remove unnecessary includes from headers.

Each header should only include the other headers it needs to compile;
`devtools/reduce-includes.sh */*.h` does this.  The C files then need
additional includes if they don't compile.

And remove the entirely useless wire/onion_wire.h, which only serves to include wire/onion_wiregen.h.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

plugins/libplugin.c

@@ -3,11 +3,13 @@
 #include <bitcoin/privkey.h>
 #include <ccan/io/io.h>
 #include <ccan/json_out/json_out.h>
+#include <ccan/membuf/membuf.h>
 #include <ccan/read_write_all/read_write_all.h>
 #include <ccan/tal/path/path.h>
 #include <ccan/tal/str/str.h>
 #include <common/daemon.h>
 #include <common/deprecation.h>
+#include <common/features.h>
 #include <common/json_filter.h>
 #include <common/json_param.h>
 #include <common/json_parse_simple.h>
@@ -17,6 +19,7 @@
 #include <common/route.h>
 #include <common/trace.h>
 #include <errno.h>
+#include <inttypes.h>
 #include <plugins/libplugin.h>
 #include <stdio.h>
 #include <sys/socket.h>