Enable seq to be imported from baker

Enable the seq() function to be imported from the baker module like
it is in the recipe module so that it can be used as baker.seq() if
preferred or to avoid namespace issues.

The current import can be left in place for backwards compatibility
or to continue importing seq as before.

Closes model-bakers#75

docs/source/recipes.rst

@@ -225,20 +225,18 @@ Sometimes, you have a field with an unique value and using ``make`` can cause ra
 
 This will append a counter to strings to avoid uniqueness problems and it will sum the counter with numerical values.
 
-Sequences and iterables can be used not only for recipes, but with ``baker.make`` as well:
+Sequences and iterables can be used not only for recipes, but with ``baker`` as well:
 
 .. code-block:: python
 
 
-    # it can be imported directly from model_bakery
-    >>> from model_bakery import seq
     >>> from model_bakery import baker
 
-    >>> customer = baker.make('Customer', name=seq('Joe'))
+    >>> customer = baker.make('Customer', name=baker.seq('Joe'))
     >>> customer.name
     'Joe1'
 
-    >>> customers = baker.make('Customer', name=seq('Chad'), _quantity=3)
+    >>> customers = baker.make('Customer', name=baker.seq('Chad'), _quantity=3)
     >>> for customer in customers:
     ...     print(customer.name)
     'Chad1'

model_bakery/baker.py

@@ -29,6 +29,8 @@
     InvalidCustomBaker,
 )
 from .utils import import_from_str
+# Enable seq to be imported from baker
+from .utils import seq  # NoQA
 
 recipes = None