Added Notifications and Light/Dark mode options in settings

[jaivsh]

Description

For #357, I've enhanced the settings page's capabilities by adding relevant options such as Light mode/Dark mode switch and Notifications button to enable or disable the app's local push notifications. I've also initialized local push notifications in the app.

For #368, I've resolved the UI conflict in the home-screen. It now is similar to the rest of the app's UI screens.

Fixes #357

Fixes #368

Have you read the Contributing Guidelines on Pull Requests?

• [x] Yes
• [x] No

Type of change

Please delete options that are not relevant.

• [x] New feature (non-breaking change which adds functionality)

Checklist:

• [x] My code follows the style guidelines(Clean Code) of this project
• [x] I have performed a self-review of my own code
• [x] My changes generate no new warnings
• [x] I have added tests/screenshots(if any) that prove my fix is effective or that my feature works.

[jaivsh]

@avinashkranjan please see the PR. Thanks!