Allow setting SMTP config
Continuation from work at https://framagit.org/framasoft/framadate/merge_requests/200
Related to https://framagit.org/framasoft/framadate/issues/192
Closes #192 (closed), #150
Edited by Thomas
Continuation from work at https://framagit.org/framasoft/framadate/merge_requests/200
Related to https://framagit.org/framasoft/framadate/issues/192
Closes #192 (closed), #150