Implement Command History

[winstonlimjy]

• Write to text file upon every command. Fixes #137.
• Up-arrow key signifies previous command. Fixes #138.
• Down-arrow key signifies next command.
• Read from text file upon up/down arrow key. Fixes #144.
• Clear text file upon exit. Fixes #157.
• Create relevant test cases. Fixes #163

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 76.38889% with 34 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/main/java/seedu/address/ui/CommandBox.java	0.00%	14 Missing :warning:
...a/seedu/address/storage/CommandHistoryStorage.java	86.48%	5 Missing and 5 partials :warning:
.../seedu/address/logic/parser/AddressBookParser.java	71.42%	4 Missing :warning:
src/main/java/seedu/address/ui/MainWindow.java	0.00%	2 Missing :warning:
src/main/java/seedu/address/MainApp.java	0.00%	1 Missing :warning:
...rc/main/java/seedu/address/model/ModelManager.java	66.66%	1 Missing :warning:
...rc/main/java/seedu/address/model/client/Email.java	0.00%	0 Missing and 1 partial :warning:
...rc/main/java/seedu/address/model/client/Phone.java	0.00%	0 Missing and 1 partial :warning:

Files with missing lines	Coverage Δ	Complexity Δ
...va/seedu/address/logic/commands/CommandResult.java	100.00% <100.00%> (ø)	15.00 <4.00> (+2.00)
...java/seedu/address/logic/commands/ExitCommand.java	100.00% <100.00%> (ø)	2.00 <1.00> (ø)
...java/seedu/address/logic/commands/HelpCommand.java	100.00% <100.00%> (ø)	2.00 <1.00> (ø)
...ress/logic/commands/NextCommandHistoryCommand.java	100.00% <100.00%> (ø)	7.00 <7.00> (?)
.../logic/commands/PreviousCommandHistoryCommand.java	100.00% <100.00%> (ø)	7.00 <7.00> (?)
src/main/java/seedu/address/model/Model.java	100.00% <ø> (ø)	1.00 <0.00> (ø)
src/main/java/seedu/address/MainApp.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
...rc/main/java/seedu/address/model/ModelManager.java	92.42% <66.66%> (-1.23%)	29.00 <1.00> (+1.00)	:arrow_down:
...rc/main/java/seedu/address/model/client/Email.java	90.00% <0.00%> (ø)	11.00 <0.00> (ø)
...rc/main/java/seedu/address/model/client/Phone.java	90.00% <0.00%> (ø)	11.00 <0.00> (ø)
... and 4 more