Switch to automapper

[SimonGeering]

Add automapper and mapping profile unit tests.

[SimonGeering]

Happy to do a PR for this if you want to assign it to me @benrick, though this may need you to PR the mapping code in from your branch that you did on stream, tbh I haven't check if its in main or not yet.

[SimonGeering]

Waiting on merge of #39 before I look at this.