Fix fom src

This MR is an updated version of MR 179. I had to create a new branch after changes in MR 185.

I have removed loss outputs since there isn't a specific printable value for all models, and there will be output logs even if the user doesn't provide an input as we discussed. With this MR, we will have a basic version of FOM for v2 as we need urgently. Tests are passing (except 4 tests of ordinal) and I recommend merging this MR as soon as possible. We can address potential improvements in further discussions.

For example, local tests create a logs directory which should be fixed. But I think it could be the topic of the further merge requests.