[enh] oscar theme redesign added

The original code made by @logico-dev (#559)

searx/static/themes/oscar/less/logicodev/oscar.less

@@ -0,0 +1,17 @@
+@import "variables.less";
+
+@import "navbar.less";
+
+@import "footer.less";
+
+@import "checkbox.less";
+
+@import "results.less";
+
+@import "infobox.less";
+
+@import "search.less";
+
+@import "cursor.less";
+
+@import "code.less";