Implement merging of GTFS and Netex Datasources

[MickJar]

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Expected behavior

When using a GTFS and a Netex datasource both datasets should be searchable

Observed behavior

Only the Netex datasource is searchable.

Version of OTP used (exact commit hash or JAR name)

Merge remote-tracking branch 'upstream/dev-2.x' into dev-2.x
Commit Hash: ad77496

Data sets in use (links to GTFS and OSM PBF files)

Any dataset where both a Netex and GTFS datasource is supplied.

Command line used to start OTP

java -jar .\otp-2.1.0-SNAPSHOT-shaded.jar --build OTP2 --save

Router config and graph build config JSON

Router config was not used.

Build-config.json:

{
  "areaVisibility": true,
  "parentStopLinking": true,
  "platformEntriesLinking": true,
  "osmWayPropertySet": "norway",
  "islandWithoutStopsMaxSize": 5,
  "islandWithStopsMaxSize": 5,
  "dataImportReport": true,
  "useTransit": true,
  "netex" : {
    "moduleFilePattern" : ".*-netex\\.zip",
    "sharedFilePattern" : "(\\w{2})_stops.xml",
    "sharedGroupFilePattern" : "(\\w{2})_shared_data.xml",
    "groupFilePattern" : "(\\w{2})_line.*\\.xml",
    "netexFeedId": "ST"
  }
}

Steps to reproduce the problem

1. Run and Build graph object through command line
2. Run OpenTripPlanner with built graph
3. Observe through searching that only search results from one of the datasources is available.