Add support for MobileNet v2 in Ethos-U55 and arm baremetal runner (#3056)

Summary:
- Builds on TOSA support for mv2
- Currently has accuracy issues for on-target execution.
- Adding support mv2 from examples/models (torchvision mv2)
- Adds ability to use portable Q/DQ ops to enable float signature quantized models (to be improved with int signature when possible to enable integer images rather than int -> float -> quant flow.
- Adds permute for ethos-u backend to enable NCHW to NHWC (which we'll aim to replace with a compiler pass on entry/exit of the subgraph, or the NHWC support when available.
- small fix to enable qantized ops in runtime for the IOQDQ pass, and build/register those kernels/ops in bare metal build

Pull Request resolved: https://github.com/pytorch/executorch/pull/3056

Reviewed By: kimishpatel

Differential Revision: D56305502

Pulled By: digantdesai

fbshipit-source-id: afa5d8aec596e7adbf099fa1653f30d7f9a2e27a