Mark config fixtures as deprecated

[lenaorobei]

In the scope of #167 the support for @magentoConfigFixture annotation was added. As the result all fixtures that was created in order to archive the same goal, need to be marked as deprecated.

ToDo:

1. Search for comment with reference to the Add support for '@magentoConfigFixture' annotation on API-functional tests #167 issue in fixtures. Example: // TODO: Should be removed in scope of https://github.com/magento/graphql-ce/issues/167.
2. Mark fixtures as @deprecated.
3. Add comment about @magentoConfigFixture annotation.

Acceptance criteria:

1. Fixtures with reference Add support for '@magentoConfigFixture' annotation on API-functional tests #167 to are marked as deprecated.
2. Explanatory comment about @magentoConfigFixture annotation is added.
3. No tests are using deprecated fixtures.