Refactor alert component and alert dialog into function component

[saberlynx]

Checklist:

• Tests
• CHANGELOG Entry

[codecov]

Codecov Report

Merging #2406 into master will increase coverage by 0.08%.
The diff coverage is 24.10%.

@@            Coverage Diff             @@
##           master    #2406      +/-   ##
==========================================
+ Coverage   54.89%   54.97%   +0.08%     
==========================================
  Files        1093     1094       +1     
  Lines       26603    26573      -30     
  Branches     7570     7537      -33     
==========================================
+ Hits        14603    14608       +5     
+ Misses      10895    10859      -36     
- Partials     1105     1106       +1     

Impacted Files	Coverage Δ
gsa/src/web/pages/alerts/dialog.js	21.18% <1.44%> (+0.84%)	⬆️
gsa/src/web/utils/stateReducer.js	14.28% <14.28%> (ø)
gsa/src/web/pages/alerts/component.js	22.22% <37.81%> (+3.13%)	⬆️
gsa/src/web/entities/container.js	45.71% <0.00%> (+1.22%)	⬆️

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[bjoernricks]

The whole alert dialog and it's state handling is still way to difficult and hard to understand. I really think we need to come up with a new concept for the alert dialog in future.