Update isSamePerson() equality for Person class

The person equality check returns true if the name or the email
matches. The OR condition complicates the equality check done when
editing a person as it assumes isSamePerson() to have a transitive
relation.

Alternative 1: Improve the way the equality check is done in the edit
command to prevent the above bug. (PRs nus-cs2103-AY2122S2#68, nus-cs2103-AY2122S2#69)

Alternative 2: Simplify the equality check by removing the OR condition.
This is simpler but possibly too strict for the address book domain
i.e., increases the risk of duplicate entries for the same person
creeping into the address book

We decided to go with the alternative 2 because,
* It is important to keep the code base simple, to reduce the initial
learning curve of the students at the start of their project
* Students can introduce a more sophisticated equality check that
matches their product domain later.

Also, let's change the default name in PersonBuilder utility class.
This is because AddCommandIntegrationTest populates its model using
getTypicalPersons() which contains a person with the default name.
This test then creates another person using the default name, to be
added into the model, which is expected to pass. However, the above
update in equality causes this test to fail. Thus we need to change the
default name to a unique name that is not inside getTypicalPersons().
Also, the default email is changed for consistency in naming the
default values, it does not affect current test cases.

src/main/java/seedu/address/model/person/Person.java

@@ -22,19 +22,17 @@ public class Person {
 
     // Data fields
     private final Address address;
-    private final Remark remark;
     private final Set<Tag> tags = new HashSet<>();
 
     /**
      * Every field must be present and not null.
      */
-    public Person(Name name, Phone phone, Email email, Address address, Remark remark, Set<Tag> tags) {
+    public Person(Name name, Phone phone, Email email, Address address, Set<Tag> tags) {
         requireAllNonNull(name, phone, email, address, tags);
         this.name = name;
         this.phone = phone;
         this.email = email;
         this.address = address;
-        this.remark = remark;
         this.tags.addAll(tags);
     }
 
@@ -54,10 +52,6 @@ public Address getAddress() {
         return address;
     }
 
-    public Remark getRemark() {
-        return remark;
-    }
-
     /**
      * Returns an immutable tag set, which throws {@code UnsupportedOperationException}
      * if modification is attempted.
@@ -116,10 +110,7 @@ public String toString() {
                 .append("; Email: ")
                 .append(getEmail())
                 .append("; Address: ")
-                .append(getAddress())
-                .append(" Remark: ")
-                .append(getRemark());
-
+                .append(getAddress());
 
         Set<Tag> tags = getTags();
         if (!tags.isEmpty()) {