Add Token Value automatically as CSS Selector

In first place we decided that templates provide additional information about their properties via a properties file. Currently there is only one value: is-css-value (e.g. technical-dept.quality.is-css-value).

It is somewhat cumbersome to define this file, especially for user templates. Therefore we decided that we add every value that is a token (e.g. contains no whitespaces and is under 128 characters long as a value selector).