[#1248] Redirect user to next after login

[vaszig]

Next is not used somewhere in the project (for instance if we click from an email the link to approve a contact we are not redirected to the contacts) so I added it for all the possible login methods.

[codecov-commenter]

Codecov Report

Merging #550 (13c0973) into develop (f0437e6) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop     #550      +/-   ##
===========================================
+ Coverage    96.47%   96.49%   +0.01%     
===========================================
  Files          540      541       +1     
  Lines        19216    19291      +75     
===========================================
+ Hits         18539    18614      +75     
  Misses         677      677              

Impacted Files	Coverage Δ
src/open_inwoner/accounts/tests/test_auth.py	100.00% <100.00%> (ø)
.../open_inwoner/components/templatetags/link_tags.py	94.54% <100.00%> (+0.66%)	⬆️

... and 5 files with indirect coverage changes

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