add ability to provide an alternate Field for highlighting

* TypoScript configuration
* add parameters to Solr query
* use alternate field in Field/Content partial
edfu: explicit highlighting configuration

we cannot use * when dealing with alternate fields (because Solarium appends the [wrong](https://github.com/basdenooijer/solarium/issues/185) field names [to hl.fl](https://github.com/basdenooijer/solarium/issues/186) which [Solr then ignores](https://issues.apache.org/jira/browse/SOLR-5127)