Provide interface to the precs API of LinearSolve

[j-fu]

No description provided.

[termi-official]

I think this PR requires bumping LinearSolve.jl to v3, because it uses the new API - can you confirm @oscardssmith ?

[oscardssmith]

confirmed

[j-fu]

In fact it already worked with LinearSolve 2.37 . The switch 2.x -> 3.x was a little bit bumpy on lts, may be there are some users out there who would appreciate to be able to work with 2.x.

[termi-official]

I see, thanks for clarifying Jürgen. Should we still add the 2.37 as lower compat or at least include some kind of warning when constructing the builder on an old version?

[j-fu]

Ah I did not see that AMG already depends on LinearSolve for the coarse grid solve. The nice thing about the precs API is that it does not need to import anything from LinearSolve.

Under these circumstances, IMHO we should have for compat either "2.37,3" or "2,3". I prefer the former. In the later case, I think those who want to use the precs API already know to ensure to have a sufficiently new LinearSolve, so IMHO we wouldn't need a warning.

[termi-official]

Yea I introduced LinearSolve directly to give users better, modular control over used the coarse level solver.