There is a requirement for the colour of the banner to be different to the single id colour. In order to accomodate that we are adding two new columns for that data.
These columns will be updated manually and not done with a data migration.
A new column called domain has been added. This will be used as a default domain, if the user that creates the service has a matching domain this email brand will be set for the service.
This PR only adds the new columns to the model and db.
https://www.pivotaltracker.com/story/show/159660295
The admin app still needs to use the name column.
Add the text field to the post data schemas.
If the text is not in the post data, then populate it with the data in the name field.
This should make the migration to text easier, and will work until we are able to update the admin app.
notable things that have been kept until migration is complete:
* passing in `organisation` to update_service will update email branding
* both `/email-branding` and `/organisation` hit the same code
* service endpoints still return organisation as well as email branding
