Add support for city name dynamic redirects

[acelaya]

Closes #1774

Add a new type of condition for the dynamic rule-based redirection system.

This condition checks if the city name resulting of geolocating current visitor matches configured one.

This condition will never match if geolocation is not configured, or it is disabled, and there's always a chance of a visitor to be incorrectly geolocated, so there's a small chance of false negatives/positives.

The city name is also not validated, so human errors or typos would also result in incorrect matchings.

Additionally, Shlink won't warn you if geolocation is not configured/enabled when a condition of this type is created.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.70%. Comparing base (7ddb3e7) to head (a6e0916).
Report is 3 commits behind head on develop.

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #2263      +/-   ##
=============================================
+ Coverage      93.68%   93.70%   +0.01%     
- Complexity      1647     1655       +8     
=============================================
  Files            272      272              
  Lines           5768     5781      +13     
=============================================
+ Hits            5404     5417      +13     
  Misses           364      364              

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