Add headway to GTFS GraphQL API

[heeleeaz]

Summary

This PR adds headway to Plan Itinerary.Leg

Issue

#5950

Unit tests

No Unit test required

Documentation

• Documentation is included in the GraphQL model.

[leonardehrenfried]

Can you return a Duration here? We already have the scalar for it.

[leonardehrenfried]

Are you using this API or the GTFS one? If you don't use it, you don't need to add this code here.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.46%. Comparing base (bd2eced) to head (2eaf8ea).
Report is 3 commits behind head on dev-2.x.

Additional details and impacted files

@@            Coverage Diff             @@
##             dev-2.x    #5951   +/-   ##
==========================================
  Coverage      69.46%   69.46%           
+ Complexity     17075    17074    -1     
==========================================
  Files           1937     1937           
  Lines          73717    73725    +8     
  Branches        7546     7546           
==========================================
+ Hits           51204    51211    +7     
  Misses         19882    19882           
- Partials        2631     2632    +1     

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[leonardehrenfried]

Please also add a test for the new field.

1. Add it to the query here: https://github.com/opentripplanner/OpenTripPlanner/blob/12c51f44f204db31d34a1eeb0d59204226e0fa5d/src/test/resources/org/opentripplanner/apis/gtfs/queries/plan-extended.graphql#L1-L0
2. Fill the data set with a frequency leg here:

   OpenTripPlanner/src/test/java/org/opentripplanner/apis/gtfs/GraphQLIntegrationTest.java

   Lines 194 to 199 in 119927e

   	Itinerary i1 = newItinerary(A, T11_00)
   	.walk(20, B, List.of(step1, step2))
   	.bus(busRoute, 122, T11_01, T11_15, C)
   	.rail(439, T11_30, T11_50, D)
   	.carHail(D10m, E)
   	.build();

[leonardehrenfried]

I'm going to convert this to a draft. Once you start working on it again, you can turn it back into a PR.