Update task model

[TanishqSingla]

Overview

The current task model is outdated, and needs to be updated. The following suggestions are made by comparing data from url https://api.realdevsquad.com/tasks
Missing fields

• percentCompleted: number
• priority: string
  Misc
• taskId is actually id
• assignee type is string | boolean as noticed from the data

Optional fields

• feature key is missing on many objects
• links
• participants

[bajajcodes]

@TanishqSingla Please provide set of values for constant fields.

[TanishqSingla]

Currently there is no clarity for constant fields, this would require a discussion.
cc. @ankushdharkar @vinayak-trivedi