* WIP

* WIP

* WIP

* WIP

* style

* WIP

* WIP

* Add err msg

* Fix headers and cleanup

*  WIP graph pass to lower ngraph to ngraph dialect

* resolved compiler errors

* - refactor ngraph-dialect to graph pass

* - fix compilation issue
- unit test passes

*  - style fix

* Addressed PR comments

* - move NgDialectConversionPass to anonymous namespace

* - use getModule() to access module inside the graph pass
- address PR comments

*  - fix failing unit test case for negative padding
- make builder as an object isntead of pointer to an object

* Address PR Comments

* Re-organize files. Create MLIR backend classes

* WIP

* Refactored. Code compiles

* Moved context to Runtime class to outlive compilation and execution

* style-apply

* Base Runtime class. Few other modifications

* Minor fixes

* Fixed Runtime::run() to take type-erased pointer

* renamed core compiler

* rename backend compiler

* rename runtime compiler

* PR feedback

* Fix build fails