Create Conversation over the API

# Current Situation

- When a user reports an issue over our app, we send an email to our support inbox to create a conversation (and a ticket).

- this is necessary, because we get the error details from the app

# Pain point

- When the conversation is created, the associated contact is our own email address and not the actual user who reported the issue

- For every issue that comes over this channel, we need to disassociate our support-email address, search for the actual user and associate them

# Use Case

- create the conversation over the conversations-api and set the correct user

- for tickets, this is possible over the tickets-endpoint, but no conversation is created (which we need)