feat: port create_table to the async python API and the remote rust API (#1031)

I've also started `ASYNC_MIGRATION.MD` to keep track of the breaking
changes from sync to async python.

nodejs/src/table.rs

@@ -68,13 +68,17 @@ impl Table {
     }
 
     #[napi]
-    pub async fn count_rows(&self, filter: Option<String>) -> napi::Result<usize> {
-        self.table.count_rows(filter).await.map_err(|e| {
-            napi::Error::from_reason(format!(
-                "Failed to count rows in table {}: {}",
-                self.table, e
-            ))
-        })
+    pub async fn count_rows(&self, filter: Option<String>) -> napi::Result<i64> {
+        self.table
+            .count_rows(filter)
+            .await
+            .map(|val| val as i64)
+            .map_err(|e| {
+                napi::Error::from_reason(format!(
+                    "Failed to count rows in table {}: {}",
+                    self.table, e
+                ))
+            })
     }
 
     #[napi]