init layouts and styles for user notifications view

[thinknoack]

this provides the default styling and layouts for notifications with some dummydata. I think it is good to review and I will write tests once the data is correct. Let me know if that works.

[codecov]

Codecov Report

Attention: Patch coverage is 77.31959% with 88 lines in your changes missing coverage. Please review.

Project coverage is 47.33%. Comparing base (595bbe8) to head (d1ae3aa).

Files with missing lines	Patch %	Lines
.../src/scripts/users/user-notification-accordion.tsx	68.75%	50 Missing ⚠️
...-app/src/scripts/users/user-notifications-view.tsx	82.52%	18 Missing ⚠️
...c/scripts/users/user-notifications-tab-content.tsx	83.52%	14 Missing ⚠️
...o-app/src/scripts/users/user-notification-list.tsx	77.77%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3298      +/-   ##
==========================================
+ Coverage   47.02%   47.33%   +0.30%     
==========================================
  Files         583      586       +3     
  Lines       36947    37329     +382     
  Branches     1174     1203      +29     
==========================================
+ Hits        17375    17669     +294     
- Misses      19385    19473      +88     
  Partials      187      187              

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