[Test] Configure Repo with CI and Create Test for ecomm/store

[timmyc]

In order to improve the quality of the experience in the ecommerce plan, we need to begin implementing test coverage for the functionality implemented within the Calypso Bridge plugin. There is a test suite now with only example assertions, so for this issue, let's create a test that asserts the proper set of logic is loaded for both scenarios:

• Assert the proper code path is taken for ecomm plan sites
• Assert the proper code is executed for Store on WPCOM sites.

Lastly we need to setup CI on this repository to run the test suite against each branch.

[timmyc]

I spent some time trying to get the test suite to run locally for me, and hit the following:

Error: Looks like you're using PHPUnit 8.0.6. WordPress is currently only compatible with PHPUnit up to 7.x. Please use the latest PHPUnit version from the 7.x branch.

So thinking we need to just get the test suite up to the current Woo Core standards so we can continue to use PHPUnit 8.x as we are in wc-admin.

Also the README instructions on the test suite here will need some <3 too.

[timmyc]

Some e2e test ideas:

• Verify that the ecomm/woo menu is rendered, and not the "plugin view" for "connected" screens. See example of this in action here
• When we implement the new OBW, and associated changes, verify that flow works as expected ( blocked by #529 )

[timmyc]

Since CI is setup now, I'm going to close this out. We can open up some e2e specific issues likely when we integrate the nav proejct.