Nedelec interpolation operator with libCEED

[sebastiangrimberg]

The interpolation operator from vector H1 to H(curl) used for high-order AMS construction is unlike the discrete gradient and curl in that it does depend on the element Jacobians. However, we can still come up with a partially-assembled form which uses the Jacobian at quadrature points as the quadrature data. See https://github.com/mfem/mfem/blob/master/fem/fe/fe_base.cpp#L1259 for H(curl) and https://github.com/mfem/mfem/blob/master/fem/fe/fe_base.cpp#L1045 for H(div). Also see https://github.com/mfem/mfem/blob/master/fem/integ/bilininteg_interp_pa.cpp#L1798 for the tensor-product element partial assembly.