Add a tox job for generating docs

Add a tox job to make it easier for developers to generate their
own docs before submitting a patch.

Change-Id: Iab7ff03120675ade8a3e6e6f7b7839be1f58d40c
Improve the method find_resourceid_by_name_or_id

Now the method find_resourceid_by_name_or_id doesn't honoured the
project id. So if a user with admin role want to create an instance
for another tenant, and using a a security group which name is
duplicated in Neutron. Then the boot will fail.

This patch is the fix on neutron client part. It will enhance the
method find_resourceid_by_name_or_id to support project id as a
parameter so as to get the correct security group id when passing
a security gruop name.

Change-Id: Ibd1829bd0f22f56c4fa210c67d10e1db5556c033
Closes-Bug: 1335733
Merge "Improve the method find_resourceid_by_name_or_id"
Merge "Add a tox job for generating docs"