Add the example DAG for azure blob storage (#1598)

# Description
## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->
- Missing documentation and example DAG for Azure blob storage

<!--
Issues are required for both bug fixes and features.
Reference it using one of the following:

closes: #ISSUE
related: #ISSUE
-->
closes: #1571

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- Add the documentation and example DAG for Azure blob storage
(non-native path)

## Does this introduce a breaking change?
No

### Checklist
- [x] Created tests which fail without the change (if possible)
- [x] Extended the README / documentation, if necessary

(cherry picked from commit bb9a636)

python-sdk/docs/astro/sql/operators/load_file.rst

@@ -288,6 +288,15 @@ Users can also load data from an FTP:
    :start-after: [START load_file_example_21]
    :end-before: [END load_file_example_21]
 
+Loading data from Azure Blob storage
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Users can also load data from an Azure Blob storage:
+
+.. literalinclude:: ../../../../example_dags/example_load_file.py
+   :language: python
+   :start-after: [START load_file_example_25]
+   :end-before: [END load_file_example_25]
+
 
 Default Datasets
 ~~~~~~~~~~~~~~~~

python-sdk/example_dags/example_load_file.py

@@ -330,4 +330,17 @@
     )
     # [END load_file_example_24]
 
+    # [START load_file_example_25]
+    aql.load_file(
+        input_file=File("wasb://astro-sdk/sample.csv", conn_id="wasb_default_conn"),
+        output_table=Table(
+            conn_id=SNOWFLAKE_CONN_ID,
+            metadata=Metadata(
+                database=os.environ["SNOWFLAKE_DATABASE"],
+                schema=os.environ["SNOWFLAKE_SCHEMA"],
+            ),
+        ),
+    )
+    # [END load_file_example_25]
+
     aql.cleanup()