Add Attribute Alias

[jamesseth]

Resources: +Create/ Update/Read Attribute Alias............ attribute_alias.py +Delete Attribute Alias....................................delete_attribute_alias.py +Get Attributes...............................................get_attributes.py

Models: +Attribute Alias.................attribute_alias.py

Unit tests:

• Test CRUD Attribute Alias ........................test_attribute_alias.py
• Test Get Attributes....................................test_get_attributes.py