Move RecordableCommands to DynamoCore

The Dynamo should be able to execute RecordableCommands in headless mode (when there is no WPF form). Thats why they should be in nonUI part of core - DynamoCore. Also their Execute method implementation should be based on DynamoModel rather than DynamoViewModel, so RecordableCommands are UI independent

This PR contains a lot of changes but most of them are minor: DynCmd.SomeCommand -> SomeCommand, DynamoViewModel.SomeCommand -> SomeCommand
Now command's Execute method is not based on dynamoViewModel anymore. To execute the same code as it was we need to use DynamoViewModel.ExecuteCommand and not to execute its 
```csharp
if (null != this.automationSettings)
           this.automationSettings.RecordCommand(command);
if (Model.DebugSettings.VerboseLogging)
           model.Logger.Log("Command: " + command);
```