Add order command

[guanquann]

• Add addorder command [addorder [INDEX] r/ [DESCRIPTION] d/ [DATE]]
• For example: addorder 1 r/ test d/ 2024-04-01
• Show the number of orders from each supplier in GUI
• Added most testing
• User guide

[codecov]

Codecov Report

Attention: Patch coverage is 99.31973% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 78.48%. Comparing base (99eb73f) to head (4ee0fa8).

Files	Patch %	Lines
src/main/java/seedu/address/ui/PersonCard.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master      #25      +/-   ##
============================================
+ Coverage     75.96%   78.48%   +2.52%     
- Complexity      444      496      +52     
============================================
  Files            72       77       +5     
  Lines          1377     1520     +143     
  Branches        133      148      +15     
============================================
+ Hits           1046     1193     +147     
+ Misses          301      297       -4     
  Partials         30       30              

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