The object collecting all DSL templates for creating new instances of JsonStringTemplates.
Any new "string" template starts as "empty", meaning that only the type of the element will be checked for matching and the template will be capable of matching any string. Then, for further specifying the template, the user can decide whether to add some values to which the string should be equal, or a regular expression which should match the string, or an inclusive range of lengths for the string to match. The interval can be half-open on both ends and those can be specified in either order.