FEATURE: Add /task command

[sahsisunny]

Overview: To facilitate task tracking for assignees, this pull request introduces a new command: /task. Users can utilize this command by providing a username as an argument to retrieve details of active tasks assigned to that user.

Description:

• The command /task accepts a username as an argument.

• Upon execution, it will return the following task details for In progress tasks assigned to the specified user:

  
  ##  **In Progress Tasks of sunny-s**
  
  **Title:** Test Cases for QR scanning feature
  **Progress:** 40%
  **Ends On:** 9 September 2023, 12:00 AM IST
  **More details:** [Task Details](Task_Link_1)
  
  **Title:** /task command to show assignee task details
  **Progress:** 50%
  **Ends On:** 9 September 2023, 10:17 AM IST
  **More details:** [Task Details](Task_Link_2)

→ All Tasks

### Screenshot
![image](https://github.com/Real-Dev-Squad/discord-slash-commands/assets/70854507/c7dfee04-f618-4e0e-9216-cf6df20696f0)

### Test Coverage
![image](https://github.com/Real-Dev-Squad/discord-slash-commands/assets/70854507/8069be16-4af8-498f-99c5-d9820fe23d22)