Changes:
-- Change name-space from Azure to sonic-net.
-- Sort yang list in setup.py for yang-models list.
#### Why I did it
Sonic repo has moved to Linux-foundation.
#### How I did it
[yang-models]: Change name-space from Azure to sonic-net.
#### How to verify it
PR Tests are good enough to verify.
Why I did it
SONiC YANG model support for BGP & route-map features.
How I did it
Defined various BGP and route-map YANG containers and lists based on config-DB schema.
How to verify it
Built the following successfully with various BGP & route-map unit test cases.
make target/python-wheels/sonic_yang_models-1.0-py3-none-any.whl
make target/python-wheels/sonic_yang_mgmt-1.0-py3-none-any.whl
