Added a donation popup to our application.

[MohitMaliFtechiz]

Fixes #3736

• The donation popup will be shown to the user every three months.
• If the user clicks the "Later" button, the popup will appear again after 3 days.
• The donation popup will only be shown when there is at least one book available in the library. If no ZIM file is present, it’s not ideal to ask for a donation, as the user has not yet used the application.
• The donation popup will only be shown for custom apps when the support_url is configured. If the support menu item is hidden in the sidebar (a feature we offer), the donation popup will not be displayed, as there is no support_url available for that custom app.

Kiwix App(When no bottomAppBar)	Kiwix App(When bottomAppBar showing)	Custom Apps

[kelson42]

@Popolechien Does the approqch sounds correct to you?

[Popolechien]

Yup very good

[codecov]

Codecov Report

Attention: Patch coverage is 24.21053% with 72 lines in your changes missing coverage. Please review.

Project coverage is 57.46%. Comparing base (681e3a0) to head (9dee134).
Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
.../kiwix/kiwixmobile/core/main/CoreReaderFragment.kt	12.06%	50 Missing and 1 partial ⚠️
...ix/kiwixmobile/core/utils/DonationDialogHandler.kt	40.74%	13 Missing and 3 partials ⚠️
...wix/kiwixmobile/core/utils/SharedPreferenceUtil.kt	50.00%	5 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #3984      +/-   ##
============================================
- Coverage     57.76%   57.46%   -0.31%     
- Complexity     1575     1587      +12     
============================================
  Files           311      312       +1     
  Lines         12865    12960      +95     
  Branches       1641     1651      +10     
============================================
+ Hits           7432     7447      +15     
- Misses         4341     4422      +81     
+ Partials       1092     1091       -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.