feat(backend): flow streaming (#6520)

* feat(backend): flow streaming

* all streaming languages + sync api

* sqlx

* fix build

* UI and nits

* nit

* feat: stream last flow step

* sqlx

* nit

* use get for stream endpoints + add snippet in UI

* refactor

* nits

* Update backend/windmill-worker/src/common.rs

Co-authored-by: graphite-app[bot] <96075541+graphite-app[bot]@users.noreply.github.com>

* nits

---------

Co-authored-by: graphite-app[bot] <96075541+graphite-app[bot]@users.noreply.github.com>

backend/windmill-worker/src/python_executor.rs

@@ -121,7 +121,7 @@ use windmill_common::s3_helpers::OBJECT_STORE_SETTINGS;
 use crate::{
     common::{
         create_args_and_out_file, get_reserved_variables, read_file, read_result,
-        start_child_process, OccupancyMetrics,
+        start_child_process, OccupancyMetrics, StreamNotifier,
     },
     handle_child::handle_child,
     worker_utils::ping_job_status,
@@ -386,6 +386,7 @@ pub async fn uv_pip_compile(
             false,
             occupancy_metrics,
             None,
+            None,
         )
         .await
         .map_err(|e| {
@@ -864,6 +865,8 @@ mount {{
         start_child_process(python_cmd, &python_path, false).await?
     };
 
+    let stream_notifier = StreamNotifier::new(conn, job);
+
     let handle_result = handle_child(
         &job.id,
         conn,
@@ -878,6 +881,7 @@ mount {{
         false,
         &mut Some(occupancy_metrics),
         None,
+        stream_notifier,
     )
     .await?;