feat/ocw/bookkeeping (#5200)

Co-Authored-By: Kian Paimani <5588131+kianenigma@users.noreply.github.com>
Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

substrate/primitives/state-machine/src/basic.rs

@@ -140,6 +140,8 @@ impl From<BTreeMap<StorageKey, StorageValue>> for BasicExternalities {
 }
 
 impl Externalities for BasicExternalities {
+	fn set_offchain_storage(&mut self, _key: &[u8], _value: Option<&[u8]>) {}
+
 	fn storage(&self, key: &[u8]) -> Option<StorageValue> {
 		self.inner.top.get(key).cloned()
 	}