Add a new filter: strftime. Use the well known function to format a date output. (#23832)

(cherry picked from commit 3f5b304fc28b6c34df9ea6a4c3531dc422ce198b)
rebased for @yannig

docs/docsite/rst/playbooks_filters.rst

@@ -644,6 +644,24 @@ To always exhaust all list use ``zip_longest``::
       debug: msg="{{ [1,2,3]|zip_longest(['a','b','c','d','e','f'], [21, 22, 23], fillvalue='X')|list }}"
 
 
+.. versionadded:: 2.4
+To format a date using a string (like with the shell date command), use the "strftime" filter::
+
+    # Display year-month-day
+    {{ '%Y-%m-%d' | strftime }}
+
+    # Display hour:min:sec
+    {{ '%H:%M:%S' | strftime }}
+
+    # Use ansible_date_time.epoch fact
+    {{ '%Y-%m-%d %H:%M:%S' | strftime(ansible_date_time.epoch) }}
+
+    # Use arbitrary epoch value
+    {{ '%Y-%m-%d' | strftime(0) }}          # => 1970-01-01
+    {{ '%Y-%m-%d' | strftime(1441357287) }} # => 2015-09-04
+
+.. note:: To get all string possibilities, check https://docs.python.org/2/library/time.html#time.strftime
+
 Debugging Filters
 `````````````````