refactor: Refactor AB3 repo-wide

[dwsc37]

Closes #48

Repo wide refactor of AB3 into KeyContacts, provide a skeleton for feature implementation.

Notable changes:

• Main package renamed from seedu.address into keycontacts
• All instances of Person have been replaced with Student
• All instances of AddressBook and other related classes (e.g. AddressBookStorage) have been replaced with StudentDirectory or its equivalents.
• Corresponding UI elements have been updated.

Documentation has not been updated.

[codecov]

Codecov Report

Attention: Patch coverage is 80.90909% with 63 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/main/java/keycontacts/MainApp.java	0.00%	13 Missing ⚠️
...in/java/keycontacts/model/util/SampleDataUtil.java	20.00%	12 Missing ⚠️
src/main/java/keycontacts/ui/StudentListPanel.java	0.00%	12 Missing ⚠️
...a/keycontacts/model/student/UniqueStudentList.java	86.95%	4 Missing and 2 partials ⚠️
src/main/java/keycontacts/ui/StudentCard.java	0.00%	6 Missing ⚠️
.../main/java/keycontacts/model/StudentDirectory.java	83.33%	3 Missing and 2 partials ⚠️
src/main/java/keycontacts/ui/MainWindow.java	0.00%	4 Missing ⚠️
src/main/java/keycontacts/logic/LogicManager.java	66.66%	2 Missing ⚠️
...n/java/keycontacts/logic/commands/EditCommand.java	96.77%	0 Missing and 1 partial ⚠️
src/main/java/keycontacts/model/UserPrefs.java	87.50%	1 Missing ⚠️
... and 1 more

Files with missing lines	Coverage Δ	Complexity Δ
src/main/java/keycontacts/AppParameters.java	95.65% <ø> (ø)	12.00 <0.00> (?)
src/main/java/keycontacts/Main.java	0.00% <ø> (ø)	0.00 <0.00> (?)
src/main/java/keycontacts/commons/core/Config.java	77.27% <ø> (ø)	9.00 <0.00> (?)
...ain/java/keycontacts/commons/core/GuiSettings.java	76.92% <ø> (ø)	8.00 <0.00> (?)
...main/java/keycontacts/commons/core/LogsCenter.java	78.78% <100.00%> (ø)	5.00 <1.00> (?)
...rc/main/java/keycontacts/commons/core/Version.java	82.50% <ø> (ø)	19.00 <0.00> (?)
...ain/java/keycontacts/commons/core/index/Index.java	100.00% <ø> (ø)	11.00 <0.00> (?)
...tacts/commons/exceptions/DataLoadingException.java	100.00% <ø> (ø)	1.00 <0.00> (?)
...acts/commons/exceptions/IllegalValueException.java	100.00% <ø> (ø)	2.00 <0.00> (?)
...rc/main/java/keycontacts/commons/util/AppUtil.java	88.88% <ø> (ø)	5.00 <0.00> (?)
... and 61 more

[IzN432]

Just some minor comments

[IzN432]

LGTM