Add Lithuanian to processing languages

SOLR doesn't support Lithuanian, maybe it can be added via plugins. A
manual setup of solr is required then. It has been added with basic
support.

Closes: #1540

modules/fts-psql/src/main/scala/docspell/ftspsql/FtsRepository.scala

@@ -193,5 +193,6 @@ object FtsRepository extends DoobieMeta {
       case Language.Latvian    => "simple"
       case Language.Japanese   => "simple"
       case Language.Hebrew     => "simple"
+      case Language.Lithuanian => "simple"
     }
 }