Add policy for PUSH require presence

[cornelinux]

In this implementation a policy defines, that the
user needs to confirm the correct choice, as
displayed in the login UI.

Working on #3897

[pep8speaks]

Hello @cornelinux! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2024-06-03 13:57:01 UTC

[codecov]

Codecov Report

Attention: Patch coverage is 91.17647% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 92.14%. Comparing base (ca819aa) to head (5b790c1).
Report is 28 commits behind head on master.

❗ Current head 5b790c1 differs from pull request most recent head f0f796b

Please upload reports for the commit f0f796b to get more accurate results.

Files	Patch %	Lines
privacyidea/lib/tokens/pushtoken.py	89.28%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3936      +/-   ##
==========================================
- Coverage   92.25%   92.14%   -0.11%     
==========================================
  Files         196      195       -1     
  Lines       25456    24855     -601     
==========================================
- Hits        23484    22903     -581     
+ Misses       1972     1952      -20     

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