Added P group feature file

Author: pbashyal-nmdp

tests/features/p_group.feature

@@ -0,0 +1,12 @@
+Feature: P Groups
+
+  Scenario Outline:
+
+    Given the allele as <Allele>
+    When reducing on the <Level> level (ambiguous)
+    Then the reduced allele is found to be <Redux Allele>
+
+    Examples:
+      | Allele        | Level | Redux Allele |
+      | B*44:15:01:01 | P     | B*44:15P     |
+      | A*02:01:01    | P     | A*02:01:01   |