Make dapp available for multiple users via REST API

[SendFlo]

1. It should be possible to create multiple accounts via REST
2. It should be possible to send a SOI-template-URL via REST
3. It should be possible to export user specific doi-information via REST

[SendFlo]

Users can be now created and updated by the admin in the restAPIaccess branch.

[SendFlo]

Doi-information are now exported by userid in export api query. In the future it should use user-id-token and auth-token.

[silkroadnomad]

Remarks: When adding an opt-in every user must authenticate and can add an opt-in (not just admin) In case admin does this, this should be not prevented. but in this case the ownerId must be given in REST request.

the template url overwrites the system default template url (and the other attributes) in the moment the email template is being sent back to Bob. It is not desirable to check all attributes (templateUrl, redirect, subject, returnPath) in the moment the user is created. it should be possible to give all attributes of the user when it is created.

Export: For the export interface we do the same thing: 1) the admin can export all opt-ins from all users (showing the owner for every opt-in) 2) the admin adds a query parameter for the onwer and receives only those. 3) a user can authenticate and see's only his opt-ins.

[SendFlo]

• Authenticated users now can add opt-ins

• Template information is now optional on user creation and overwrites default template when fetched, if it exists

• Users can now export their opt-ins, admin can export all or just user specific

[SendFlo]

Need to add PUT call for users collection for users to be able to update their account-profile. Admin user should still be able to update user-profiles based on userid.

[silkroadnomad]

needs software tests. pls see #64 and #65