[Part 2] Create convenience constructor for the listed Transforms.

[zeahmed]

This work item is related to #371 and is the 2nd work item in series of creating convenience constructor (cf. #380). In this work item, convenience constructors will be created following set of transforms.

• ChooseColumnsTransform.cs
• ConvertTransform.cs
• DropSlotsTransform.cs
• GenerateNumberTransform.cs
• HashTransform.cs
• KeyToValueTransform.cs
• KeyToVectorTransform.cs
• LabelConvertTransform.cs
• LabelIndicatorTransform.cs
• RangeFilter.cs
• ShuffleTransform.cs
• SkipTakeFilter.cs
• TermTransform.cs