* [MLIR] Add `ngraph` prefix to MLIR flags

Some flags collision with some MLIR flags.

* [MLIR] Add support for nGraph tensor type in parser

Initial commit that enables nGraph parsing. It's needed for testing.

* Rename ngraph print flag

* Rename ngraph dump mlir flags

* Clang format

* Revert "[MLIR] Add support for nGraph tensor type in parser"

This reverts commit ae371d6a5c8ea590322d5d3b9ba110159d4bf5fa.