[tosa_mlir_translator] Support dynamic tensors

This adds serialization and deserialization support for:
  -  unranked tensors (eg, *xi32) and
  -  tensors with dynamic shapes (eg, ?x?xi32)

Signed-off-by: Tai Ly <tai.ly@arm.com>
Change-Id: Ib2943333d8e3a199cf8a909b6db7197150666700