UI to display notifications

[neslihanturan]

Hi team, I implemented a sketch for notifications activity. Currently I manually entered some notifications, of course NotificationController class needs to fetch notifications from servers. This PR can be considered an UI implementation and a rough structural implementation.

Fix for #7 , here is how it looks:

[codecov-io]

Codecov Report

Merging #1024 into master will decrease coverage by 0.04%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master   #1024      +/-   ##
=========================================
- Coverage    3.71%   3.66%   -0.05%     
=========================================
  Files         104     109       +5     
  Lines        5143    5210      +67     
  Branches      489     491       +2     
=========================================
  Hits          191     191              
- Misses       4939    5006      +67     
  Partials       13      13

Impacted Files	Coverage Δ
.../fr/free/nrw/commons/di/ActivityBuilderModule.java	0% <ø> (ø)	⬆️
...nrw/commons/notification/NotificationActivity.java	0% <0%> (ø)
...free/nrw/commons/theme/NavigationBaseActivity.java	22.98% <0%> (-0.83%)	⬇️
...mmons/notification/NotificationAdapterFactory.java	0% <0%> (ø)
...fr/free/nrw/commons/notification/Notification.java	0% <0%> (ø)
...nrw/commons/notification/NotificationRenderer.java	0% <0%> (ø)
...w/commons/notification/NotificationController.java	0% <0%> (ø)
... and 2 more

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[misaochan]

@neslihanturan Awesome! Yes, please feel free to create a new branch and submit the PR to it. :)

[maskaravivek]

Am going ahead and merging this PR so that I can take it forward from here.