support init_jacobians with sparse matrices
Release notes
Add the possibility to initialize the jacobian of a discipline with sparse zeros matrices .
Problem to solve
Ease implementation of large disciplines with a lot of zeros sub-jacobians.
Proposal
have a method that do that the same way as _init_jacobians(with_zeros=True)
but using csr_matrix to be chosen by the user.
Intended users
Advanced users.
User experience goal
Reduce implementation time.
Further details
Avoid having useless memory consumption due to wrong allocation. @gallardf @alexandre.scotto