remove date from core, app_wasm.html

src/os/os.h

@@ -0,0 +1,12 @@
+typedef struct os_date_t os_date_t;
+struct os_date_t {
+    u16 ms;
+    u16 sec;
+    u16 min;
+    u16 hour;
+    u16 day;
+    u16 month;
+    u16 year;
+};
+
+fn os_date_t os_date_now(void);