feat(notification): implement notification in the mobile app

[aman-singh7]

Signed-off-by: Aman aman2@me.iitr.ac.in

Fixes #239

Describe the changes you have made in this PR -

Screenshots of the changes (If any) -

Note: Please check Allow edits from maintainers. if you would like us to assist in the PR.

[coveralls]

Pull Request Test Coverage Report for Build 3034548347

• 23 of 179 (12.85%) changed or added relevant lines in 10 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-1.5%) to 64.616%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/ui/views/cv_landing_view.dart	7	12	58.33%
lib/ui/components/cv_drawer.dart	0	7	0.0%
lib/viewmodels/notifications/notifications_viewmodel.dart	2	29	6.9%
lib/services/notifications_service.dart	0	32	0.0%
lib/models/notification.dart	0	41	0.0%
lib/ui/views/notifications/notifications_view.dart	1	45	2.22%
<!--	Total:	23	179	12.85%	-->

Files with Coverage Reduction	New Missed Lines	%
lib/services/API/group_members_api.dart	1	75.0%
lib/services/API/projects_api.dart	1	86.23%
<!--	Total:	2		-->

Totals
Change from base Build 2898848819:	-1.5%
Covered Lines:	4034
Relevant Lines:	6243

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💛 - Coveralls

[manjotsidhu]

@aman-singh7 Can you share screenshots or recording if possible ?

[aman-singh7]

@manjotsidhu The notification API is still not complete. I have implemented the basic structure of the notification feature. Here are the screenshots.