Canada SSO: simple integration tests.

#### What's this PR do?
- Provides simple integration tests for Canada SSO setup and login

#### How should this be manually tested?
- Setup `DS_CA_USER` and `DS_CA_PASS` variables in VM `/etc/environment`
- Run `ds test canada`
![image](https://cloud.githubusercontent.com/assets/672669/4669668/16692032-5570-11e4-9539-f35357053a80.png)
\* Js error is not relevant to this ticket

#### Any background context you want to provide?
Now SSO test contain only login, will be extended when the registration is ready.

#### What are the relevant tickets?
- Part of [#DS-379](https://jira.dosomething.org/browse/DS-379): Move functionality common to UK and Canada to the new nodule.
I really don't like hardcoding user and password.

Yes, it's just a temporary measure.
When the registration implementation is complete, I'll use same flow as in UK with generated users, so I'll know the password in advance.