feat: add JPA @EmbeddedId support

[igdianov]

This is a new feature PR to support JPA @EmbeddedId attribute mappings submitted by @ludovicmotte,

Given, the following entity class definition with @EmbeddableId :

@Entity(name = "Boat")
@Data
public class Boat  {

    @Embeddable
    @Data
    public static class BoatId implements Serializable {
        private static final long serialVersionUID = 1L;

        String id;
        String country;
     }

    @EmbeddedId
    @GraphQLDescription("Primary Key for the Boat Class")
    BoatId boatId;

    @Embedded
    Engine engine;
}

Will generate schema to query entities using embedded id attributes:

Singular Query Field:

query { 
   Boat( boatId: { id: "1" country: "EN" } ) { 
       boatId { 
         id country 
       } 
       engine { 
         identification 
      } 
   } 
}

Plural Query Field:

query { 
  Boats { 
     select { 
        boatId( where: { id: { EQ: "1"} country: { EQ: "EN"}}) {
           id country
        } 
        engine { 
           identification 
        }
    } 
  } 
}

[codecov]

Codecov Report

Merging #84 into master will increase coverage by 1.43%.
The diff coverage is 93.45%.

@@             Coverage Diff              @@
##             master      #84      +/-   ##
============================================
+ Coverage      60.4%   61.84%   +1.43%     
- Complexity      283      302      +19     
============================================
  Files            31       31              
  Lines          1816     1853      +37     
  Branches        282      286       +4     
============================================
+ Hits           1097     1146      +49     
+ Misses          593      580      -13     
- Partials        126      127       +1

Impacted Files	Coverage Δ	Complexity Δ
...query/schema/impl/GraphQLJpaSimpleDataFetcher.java	91.3% <92.85%> (+1.3%)	7 <6> (+4)	⬆️
...jpa/query/schema/impl/GraphQLJpaSchemaBuilder.java	86.69% <93.54%> (+0.74%)	80 <19> (+10)	⬆️
...hql/jpa/query/schema/impl/JpaPredicateBuilder.java	46.11% <0%> (+1.45%)	41% <0%> (+1%)	⬆️
...a/query/schema/impl/QraphQLJpaBaseDataFetcher.java	72.11% <0%> (+2.68%)	97% <0%> (+4%)	⬆️

---

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[codecov]

Codecov Report

Merging #84 into master will increase coverage by 1.43%.
The diff coverage is 93.45%.

@@             Coverage Diff              @@
##             master      #84      +/-   ##
============================================
+ Coverage      60.4%   61.84%   +1.43%     
- Complexity      283      302      +19     
============================================
  Files            31       31              
  Lines          1816     1853      +37     
  Branches        282      286       +4     
============================================
+ Hits           1097     1146      +49     
+ Misses          593      580      -13     
- Partials        126      127       +1

Impacted Files	Coverage Δ	Complexity Δ
...query/schema/impl/GraphQLJpaSimpleDataFetcher.java	91.3% <92.85%> (+1.3%)	7 <6> (+4)	⬆️
...jpa/query/schema/impl/GraphQLJpaSchemaBuilder.java	86.69% <93.54%> (+0.74%)	80 <19> (+10)	⬆️
...hql/jpa/query/schema/impl/JpaPredicateBuilder.java	46.11% <0%> (+1.45%)	41% <0%> (+1%)	⬆️
...a/query/schema/impl/QraphQLJpaBaseDataFetcher.java	72.11% <0%> (+2.68%)	97% <0%> (+4%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ac75192...282b486. Read the comment docs.