feat(arena.c): Added arena init and added ArenaResult

Want to handle errors with results, even if it meas boilerplate

src/arena.c

@@ -1 +1,34 @@
 #include "arena.h"
+#include <stdbool.h>
+#include <stdlib.h>
+
+ArenaResult arena_init(void *buffer, size_t size) {
+    if (buffer == NULL) {
+        ArenaResult err = {
+            .is_valid = false,
+            .err = ARENA_NULL_ARG,
+        };
+        return err;
+    }
+
+    if (size < 1) {
+        ArenaResult err = {
+            .is_valid = false,
+            .err = ARENA_INVALID_SIZE,
+        };
+        return err;
+    }
+
+    Arena new_arena = {
+        .data = buffer,
+        .size = size,
+        .offset = 0,
+    };
+
+    ArenaResult val = {
+        .is_valid = true,
+        .arena = new_arena,
+    };
+
+    return val;
+}