Enhance Medical History capabilities

[didymental]

This PR will add the following capabilities to the MedicalHistory class of the Patient:

• Automatically recording the date of the medical entry to be the date the medical entry is recorded (i.e. LocalDate.now(Zone.Id.of(Singapore)))
• Ability on the EditPatientCommandParser to break a patient's medical history into multiple medical entries, based on a CSV delimiter fashion
• Ability on the ParserUtil to break a patient's medical history into multiple medical entries, based on a CSV delimiter fashion
• Update test cases to reflect these changes

This PR partially resolves #79

[codecov-commenter]

Codecov Report

Merging #120 (e697ddb) into master (d901dd5) will increase coverage by 1.65%.
The diff coverage is 80.72%.

@@             Coverage Diff              @@
##             master     #120      +/-   ##
============================================
+ Coverage     61.38%   63.04%   +1.65%     
- Complexity      491      516      +25     
============================================
  Files            94       94              
  Lines          1800     1870      +70     
  Branches        190      205      +15     
============================================
+ Hits           1105     1179      +74     
+ Misses          636      619      -17     
- Partials         59       72      +13     

Impacted Files	Coverage Δ
...edu/address/logic/commands/EditPatientCommand.java	96.05% <50.00%> (-1.29%)	⬇️
...ava/seedu/address/model/person/MedicalHistory.java	73.07% <72.34%> (-8.75%)	⬇️
...in/java/seedu/address/logic/parser/ParserUtil.java	95.91% <92.30%> (-1.38%)	⬇️
.../java/seedu/address/storage/JsonAdaptedPerson.java	98.27% <93.33%> (-1.73%)	⬇️
...address/logic/parser/EditPatientCommandParser.java	93.33% <100.00%> (+0.74%)	⬆️
src/main/java/seedu/address/model/EntryList.java	75.00% <100.00%> (+75.00%)	⬆️
src/main/java/seedu/address/model/Entry.java	71.42% <0.00%> (+71.42%)	⬆️

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[joshenx]

Would like to check if changing the access modifier of arg multimap affects anything. Attributes should be private.

Also, how is medical history shown on UI now?

[joshenx]

Why is this attribute being changed to public? This violates OOP principles.

[didymental]

@joshenx thank you! sorry, I changed to public to help the debugging process when I was failing test cases, forgot to change back. Pushed a new commit to fix.

[joshenx]

lgtm!

[didymental]

@joshenx this is how the MedicalHistory appears on GUI currently. Currently, there's only one medical entry within each medical history of all patients. Once there are more, it'll appear like this, "24 Oct 2021 | lovesick, 25 Oct 2021 | covid positive", separated by commas.