refactor: Entire code base, thread and log usage

Boils down to:
- Include headers
- Reduce boiler plate with helpers
- Swap out explicit usages with core API layer
  and ensure the right API is configured beforehand

src/main/p3io/cmd.c

@@ -1,8 +1,8 @@
 #include <stddef.h>
 
-#include "p3io/cmd.h"
+#include "core/log.h"
 
-#include "util/log.h"
+#include "p3io/cmd.h"
 
 uint8_t p3io_get_full_req_size(const union p3io_req_any *req)
 {

src/main/p3io/frame.c

@@ -3,10 +3,11 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#include "core/log.h"
+
 #include "p3io/frame.h"
 
 #include "util/iobuf.h"
-#include "util/log.h"
 
 #define P3IO_FRAME_SOF 0xAA
 #define P3IO_FRAME_ESCAPE 0xFF