Bugfixing immobilienscout crawler

[mordax7]

Fixing the problem when user did not specify pagenumbe in the immobilienscout URL, making it loop over the same page over and over again. This caused, getting the same flat on Telegram several times.
Also fixed the rooms attribute, which was sending too much content, had to trim it.
Some small refactoring

[codecov-commenter]

Codecov Report

Merging #5 into master will increase coverage by 0.24%.
The diff coverage is 57.14%.

@@            Coverage Diff             @@
##           master       #5      +/-   ##
==========================================
+ Coverage   48.92%   49.16%   +0.24%     
==========================================
  Files           7        7              
  Lines         419      421       +2     
  Branches       49       49              
==========================================
+ Hits          205      207       +2     
  Misses        206      206              
  Partials        8        8              

Impacted Files	Coverage Δ
flathunter/crawl_immobilienscout.py	52.94% <57.14%> (+1.42%)	⬆️

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[codders]

Looks good - thanks!