Periodically log when integrations are taking a while to setup (#36208)

* Periodicly log when intergrations are taking a while to setup

When one or more intergrations are taking a while to setup
it is hard to determine which one is the cause.  We can
help narrow this down for the user with a periodic log
message about which domains are still waiting to be setup
every 30s.

* 30 -> 60 per discussion

* only log when the integration is actually doing setup

* reduce, fix race in test

tests/test_bootstrap.py

@@ -1,5 +1,6 @@
 """Test the bootstrapping."""
 # pylint: disable=protected-access
+import asyncio
 import logging
 import os
 from unittest.mock import Mock
@@ -249,6 +250,7 @@ async def test_setup_hass(
     mock_mount_local_lib_path,
     mock_ensure_config_exists,
     mock_process_ha_config_upgrade,
+    caplog,
 ):
     """Test it works."""
     verbose = Mock()
@@ -259,7 +261,7 @@ async def test_setup_hass(
     with patch(
         "homeassistant.config.async_hass_config_yaml",
         return_value={"browser": {}, "frontend": {}},
-    ):
+    ), patch.object(bootstrap, "LOG_SLOW_STARTUP_INTERVAL", 5000):
         hass = await bootstrap.async_setup_hass(
             config_dir=get_test_config_dir(),
             verbose=verbose,
@@ -270,6 +272,8 @@ async def test_setup_hass(
             safe_mode=False,
         )
 
+    assert "Waiting on integrations to complete setup" not in caplog.text
+
     assert "browser" in hass.config.components
     assert "safe_mode" not in hass.config.components
 
@@ -286,6 +290,44 @@ async def test_setup_hass(
     assert len(mock_process_ha_config_upgrade.mock_calls) == 1
 
 
+async def test_setup_hass_takes_longer_than_log_slow_startup(
+    mock_enable_logging,
+    mock_is_virtual_env,
+    mock_mount_local_lib_path,
+    mock_ensure_config_exists,
+    mock_process_ha_config_upgrade,
+    caplog,
+):
+    """Test it works."""
+    verbose = Mock()
+    log_rotate_days = Mock()
+    log_file = Mock()
+    log_no_color = Mock()
+
+    async def _async_setup_that_blocks_startup(*args, **kwargs):
+        await asyncio.sleep(0.6)
+        return True
+
+    with patch(
+        "homeassistant.config.async_hass_config_yaml",
+        return_value={"browser": {}, "frontend": {}},
+    ), patch.object(bootstrap, "LOG_SLOW_STARTUP_INTERVAL", 0.3), patch(
+        "homeassistant.components.frontend.async_setup",
+        side_effect=_async_setup_that_blocks_startup,
+    ):
+        await bootstrap.async_setup_hass(
+            config_dir=get_test_config_dir(),
+            verbose=verbose,
+            log_rotate_days=log_rotate_days,
+            log_file=log_file,
+            log_no_color=log_no_color,
+            skip_pip=True,
+            safe_mode=False,
+        )
+
+    assert "Waiting on integrations to complete setup" in caplog.text
+
+
 async def test_setup_hass_invalid_yaml(
     mock_enable_logging,
     mock_is_virtual_env,