Iss #131 - Add logic to lookup user by Github ID when available

An issue exists where there are inconsistencies with the email used for commits and the associated Github user account. To patch this, a change was made to optionally include the Github username in the validation request. This will be used first when doing lookups of the user, falling back on the default flow if not set.

src/main/java/org/eclipsefoundation/git/eca/api/models/EclipseUser.java

@@ -14,6 +14,7 @@ package org.eclipsefoundation.git.eca.api.models;
 import javax.annotation.Nullable;
 
 import org.eclipsefoundation.git.eca.model.GitUser;
+
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 import com.fasterxml.jackson.databind.annotation.JsonPOJOBuilder;
@@ -37,6 +38,9 @@ public abstract class EclipseUser {
 
     public abstract boolean getIsCommitter();
 
+    @Nullable
+    public abstract String getGithubHandle();
+
     @Nullable
     @JsonIgnore
     public abstract Boolean getIsBot();
@@ -75,6 +79,8 @@ public abstract class EclipseUser {
 
         public abstract Builder setIsCommitter(boolean isCommitter);
 
+        public abstract Builder setGithubHandle(@Nullable String githubHandle);
+
         @JsonIgnore
         public abstract Builder setIsBot(@Nullable Boolean isBot);