Addition of other losses

[GuillaumeErhard]

While working on some projects I used a loss not available in the library which is the boundary loss from https://github.com/LIVIAETS/boundary-loss. The license is MIT.

I guess the code need to be reworked with the different MODE constant in mind and following current interface ?

Are there other requirement, or any idea for other loss that could be useful to add ?