Add configuration for hiding label

[ivaylo-milanov]

Add a configuration option to set the label to false, so the label won’t be added to the component. Kendo UI for jQuery already has this option with label: false, which removes the label, as shown in this Dojo.

Public Feedback Item: https://feedback.telerik.com/aspnet-core-ui/1683518-add-configuration-for-hiding-label

[aleksandarevangelatov]

The client-side API should also be updated, if passing a boolean is considered a valid option. Currently the API states only a string or a configuration object are valid configuration options.