Generate SPDE list needed as input to FEM-SPDE spatial TMB models
spdeStruct(mesh)
mesh
mesh object generated from fmesher::fm_rcdt_2d() or fmesher::fm_mesh_2d()
fmesher::fm_rcdt_2d()
fmesher::fm_mesh_2d()
spde List used as input into TMB anisotropic model