Implement find contact command for ContactList

[jonasngs]

Fixes #240

This PR relates to the implementation of a command to find a contact in the ContactList by name, following the earlier PR for Contact and ContactList refactoring.

The following classes were added:

1. FindContactCommand: to handle the finding of a Contact from the ContactList by name.
2. FindContactParser: to handle parsing of user input for a command to find a contact by name. This class is responsible for error handling when the user provides invalid or incorrect arguments.

The following classes were modified:

1. AddressBookParser: Add a case to handle find contact command .

[MatthiasLHK]

LGTM

[michael-setia]

The implementation is similar with the rest of the code. Overall, looks great to merge 👍

[codecov-io]

Codecov Report

Merging #257 into master will decrease coverage by 1.75%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master     #257      +/-   ##
============================================
- Coverage     28.49%   26.73%   -1.76%     
+ Complexity      312      308       -4     
============================================
  Files           138      143       +5     
  Lines          2218     2334     +116     
  Branches        249      261      +12     
============================================
- Hits            632      624       -8     
- Misses         1532     1655     +123     
- Partials         54       55       +1     

Impacted Files	Coverage Δ	Complexity Δ
...main/java/seedu/address/commons/core/Messages.java	0.00% <ø> (ø)	0.00 <0.00> (ø)
...java/seedu/address/logic/commands/FindCommand.java	55.55% <0.00%> (ø)	5.00 <0.00> (ø)
...edu/address/logic/commands/FindContactCommand.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
.../seedu/address/logic/parser/FindContactParser.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
...a/seedu/address/logic/parser/ModuleListParser.java	56.00% <0.00%> (-2.34%)	10.00 <0.00> (ø)
...ain/java/seedu/address/storage/StorageManager.java	0.00% <0.00%> (-44.45%)	0.00% <0.00%> (-4.00%)
...rc/main/java/seedu/address/logic/LogicManager.java	0.00% <0.00%> (-35.00%)	0.00% <0.00%> (-2.00%)
src/main/java/seedu/address/MainApp.java	0.00% <0.00%> (ø)	0.00% <0.00%> (ø%)
...java/seedu/address/storage/JsonAdaptedContact.java	0.00% <0.00%> (ø)	0.00% <0.00%> (?%)
... and 4 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 9349d73...80349a1. Read the comment docs.