Rearrange PETSc and Trilinos headers

[drwells]

We now have the following PETSc and Trilinos headers:

[drwells@archway lac]$ ls petsc_*
petsc_compatibility.h
petsc_full_matrix.h
petsc_matrix_base.h
petsc_matrix_free.h
petsc_parallel_block_sparse_matrix.h
petsc_parallel_block_vector.h
petsc_parallel_sparse_matrix.h
petsc_parallel_vector.h
petsc_precondition.h
petsc_solver.h
petsc_sparse_matrix.h
petsc_vector_base.h
[drwells@archway lac]$ ls trilinos_*
trilinos_block_sparse_matrix.h
trilinos_epetra_communication_pattern.h
trilinos_epetra_vector.h
trilinos_index_access.h
trilinos_linear_operator.h
trilinos_parallel_block_vector.h
trilinos_precondition.h
trilinos_solver.h
trilinos_sparse_matrix.h
trilinos_sparsity_pattern.h
trilinos_vector.h
trilinos_vector_base.h

The odd header here is trilinos_vector.h which contains the declaration of TrilinosWrappers::MPI::Vector. Since we removed the non-parallel vectors, I propose that we remove the parallel prefix (e.g., petsc_parallel_vector.h to just petsc_vector.h) to make things consistent and deprecate the old headers.

[drwells]

I am not sure how to make our own LinearAlgebra vectors fit but I really think we should use a consistent scheme.

[bangerth]

I think your suggestion makes sense.