Add bib field mappings for parallel fields

Adds bib field mappings for parallel series statement, title, and title
display. Uses existing convention of specifying specific marc tag and
subfields to query, but introduces `isParallelFor` field to specify what
non-880 marc tag the field value should be considered a variant of. This
is essential for 1) determining *which* 880 field to use among
potentially many 880s (`isParallelFor` can be checked against $6 value),
and also 2) for relating parallel fields to the specific primary field
by occurance number (so multiple parallel titles relate index-wise to
primary titles).

https://jira.nypl.org/browse/SCC-248

mappings/recap-discovery/field-mapping-bib.json

@@ -682,6 +682,44 @@
       }
     ]
   },
+  "Parallel series statement": {
+    "pred": "nypl:parallelSeriesStatement",
+    "jsonLdKey": "parallelSeriesStatement",
+    "paths": [
+      {
+        "marc": "880",
+        "subfields": ["3","a","x","v","l"],
+        "isParallelFor": "440"
+      },
+      {
+        "marc": "880",
+        "subfields": ["3","a","x","v","l"],
+        "isParallelFor": "490"
+      }
+    ]
+  },
+  "Parallel title": {
+    "pred": "nypl:parallelTitle",
+    "jsonLdKey": "parallelTitle",
+    "paths": [
+      {
+        "marc": "880",
+        "subfields": [ "a", "b" ],
+        "isParallelFor": "245"
+      }
+    ]
+  },
+  "Parallel title display": {
+    "pred": "nypl:parallelTitleDisplay",
+    "jsonLdKey": "parallelTitleDisplay",
+    "paths": [
+      {
+        "marc": "880",
+        "subfields": [ "a", "b", "c", "f", "g", "h", "k", "n", "p", "s" ],
+        "isParallelFor": "245"
+      }
+    ]
+  },
   "Part of": {
     "pred": "nypl:partOf",
     "jsonLdKey": "partOf",