Implement Theme Seed Color Option Using `flex_color_scheme`

[MabudAlam]

Description

Problem

The JobHunt Mobile app currently lacks the ability for users to customize the theme seed color according to their preferences. This customization option can enhance the overall user experience and allow users to personalize the app's appearance.

Solution

Implement a theme seed color customization option using the flex_color_scheme package. This package provides a flexible and easy-to-use way to create beautiful and customizable color schemes for Flutter applications.

[hemant933]

sir , assign it to me