WIP on E2E setup: now creating test user accounts

Still to do: delete test project, re-create it, add test accounts to
project as manager and member respectively.
WIP on E2E setup: delete & re-create test project

After much experimentation, I've found a way that works.
Adjust tests to use new constants module
Fix one more test to use constants module
E2E setup now working: creates users, project

The setupTestEnvironment.spec.js file sets up the project as follows:
 * Create test_runner_manager_user with correct password
 * Create test_runner_normal_user with correct password
 * Delete the project named "Test Project"
 * Create a new project named "Test Project"
 * Add test_runner_manager_user to the project as a manager
 * Add test_runner_normal_user to the project as a normal member
 * Log out so further tests can be run as a normal user