Updated DynetSharp for .NET 6.0 (#1667)

* added implicit parameter to expression casting

* added option for device specification for inputs functions like ones, zeros.

* Added GPU (and device specification) support in csharp wrapper

* Updated documentation for GPU support

* Updated markdown

* added input functions by dimensions instead of value

* added LeCunUniform and NoamOpt - c++,python,sharp, fixed bugs in dynetsharp, adjusted transformer example to work with opennmt model

* added mini-batching for dynet sharp! Also, fixed bugs, added another example, updated to work with new optimizers

* Fixed NoamOpt learning-rate curve, verified result

* Reverted not dynetsharp changes

* Removed added HeInitializer and NoamOpt

* Updated vcxProj to NetCore

* Fixed shuffle

Author: shaltielshmid