closes https://github.com/TryGhost/Team/issues/1491
With multiple newsletters feature, a site should always have at-least one newsletter by default. Also, as with the default product, the default newsletter also needs to be renamed to the site title during the setup flow.
- adds default newsletter to main and test fixtures
- updates setup flow to rename newsletter name and sender name to site title
- updates model to extend default value for fields
- updates test
refs https://github.com/TryGhost/Team/issues/1463
- Allow admins to perform all newsletter operations
- We can adjust and be more permissive in the future if needed
- Added the tests back as permissions are configured correctly now
refs: https://github.com/TryGhost/Toolbox/issues/133
- instead of just a collection of utils, we now have a class that manages fixtures
- this should allow us to change the path to fixtures, e.g. between prod/dev and test, so that different fixtures can be loaded by default
- also makes it easier to test the fixture manager code itself
- this is a small part of a bit of cleanup of our test files
- the goal is to make the existing tests clearer with a view to making it easier to write more tests
- this makes the test structure follow the codebase structure more closely
- eventually we will colocate the tests as we break the codebase down further
