Scripting: Add back joda to whitelist

Watcher still exposes some dates as joda DateTime objects. This commit
adds back joda to the painless whitelist so they can still be accessed.

closes elastic#35913

modules/lang-painless/src/main/resources/org/elasticsearch/painless/spi/joda.time.txt

@@ -0,0 +1,60 @@
+#
+# Licensed to Elasticsearch under one or more contributor
+# license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright
+# ownership. Elasticsearch licenses this file to you under
+# the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+#
+# Painless definition file. This defines the hierarchy of classes,
+# what methods and fields they have, etc.
+#
+
+# NOTE: this just minimal whitelisting of joda time, just to provide
+# convenient access via the scripting API. classes are fully qualified to avoid
+# any confusion with java.time
+
+class org.joda.time.ReadableInstant {
+  boolean equals(Object)
+  long getMillis()
+  int hashCode()
+  boolean isAfter(org.joda.time.ReadableInstant)
+  boolean isBefore(org.joda.time.ReadableInstant)
+  boolean isEqual(org.joda.time.ReadableInstant)
+  String toString()
+}
+
+class org.joda.time.ReadableDateTime {
+  int getCenturyOfEra()
+  int getDayOfMonth()
+  int getDayOfWeek()
+  int getDayOfYear()
+  int getEra()
+  int getHourOfDay()
+  int getMillisOfDay()
+  int getMillisOfSecond()
+  int getMinuteOfDay()
+  int getMinuteOfHour()
+  int getMonthOfYear()
+  int getSecondOfDay()
+  int getSecondOfMinute()
+  int getWeekOfWeekyear()
+  int getWeekyear()
+  int getYear()
+  int getYearOfCentury()
+  int getYearOfEra()
+  String toString(String)
+  String toString(String,Locale)
+}