Profile LM and LMTR

[dpo]

See numerical results in JOSS paper.

[dpo]

@MaxenceGollier It seems to me that we should be able to post an SVG profile of the solvers applied to a problem in a PR (e.g., when a label is added, similarly to the benchmarks). I'm thinking of ProfileSVG or something similar.

[MaxenceGollier]

@dpo, didn't we choose to this with a gist ?