Add "ignore case" checkbox on search filed (was : 'Set literal as query object without filter from widget")

[ch-sander]

Instead of

PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
SELECT DISTINCT ?entitlement_1 ?entitlement_1_label WHERE {
  ?entitlement_1 rdf:type <http://www.graceful17.org/ontology/entitlement>;
    <http://www.graceful17.org/ontology/called> ?entitlement_1_label;
    <http://shmarql.com/fts> ?o.
  FILTER((LCASE(?o)) = (LCASE("even")))
}
LIMIT 10000

the widget should set

PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
SELECT DISTINCT ?entitlement_1 ?entitlement_1_label WHERE {
  ?entitlement_1 rdf:type <http://www.graceful17.org/ontology/entitlement>;
    <http://www.graceful17.org/ontology/called> ?entitlement_1_label;
    <http://shmarql.com/fts>"even".
}
LIMIT 10000

http://shmarql.com/fts is a fizzysearch pattern that requires its object, a literal, directly to search the index (implemented from https://github.com/epoz/shmarql, thanks to @epoz ). This is a way to mitigate https://github.com/sparna-git/Sparnatural/issues/612

which widget or sparnatural config for the dataProperty does this trick?