Fix evaluation on cells

fix evaluation on cells in RHS and restructure the LinearImplicitSolver class

assigned to @ml2851

By laura.pfeiffer on 2023-09-01T16:05:20 (imported from GitLab)

created branch 229-fix-evaluation-on-cells to address this issue

By laura.pfeiffer on 2023-09-01T16:07:33 (imported from GitLab)

mentioned in merge request !261 (merged)

mentioned in commit 9ac9e953

closed with merge request !261 (merged)