[TASK] Restructure composer.json and update dependency to Neos
[TASK] Add database migrations
[TASK] Remove unused files
[TASK] Add package policies

Now a user should have the CfC.Mailr:CampaignManager or
CfC.Mailr:User role to be able to use the module.
[TASK] Restructure module folder paths
[TASK] Update Settings.yaml to match current Neos master