Remove use of deprecated strfttime, use enums instead of class constants

for many parts of NodaTimeAutotranslater

src/enums/NodaTimeAutotranslaterStatus.php

@@ -0,0 +1,20 @@
+<?PHP
+ /**
+  * Lists cases for whether autotranslation is possible, and in which way.
+  *
+  * @author Joshua Ramon Enslin <joshua@museum-digital.de>
+  */
+ declare(strict_types = 1);
+
+enum NodaTimeAutotranslaterStatus {
+    case NOT;
+    case AS_MONTH_DAY;
+    case AS_YEAR_WITH_SUFFIX;
+    case SINCE_START;
+    case UNTIL_END;
+    case ONLY_YEAR;
+    case CENTURY;
+    case DECADE;
+    case TIMESPAN_YEARS;
+    case TIMESPAN_DATES;
+}