Update to react-router 7

[acelaya]

Following the migration guide, update the project to react-router 7

It also updates to @shlinkio/shlink-frontend-kit 0.7, since that version supports react-router 7

[codecov]

Codecov Report

Attention: Patch coverage is 76.19048% with 5 lines in your changes missing coverage. Please review.

Project coverage is 77.36%. Comparing base (79564d6) to head (226feb4).
Report is 22 commits behind head on main.

Files with missing lines	Patch %	Lines
src/Main.tsx	66.66%	0 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #529      +/-   ##
==========================================
- Coverage   77.43%   77.36%   -0.07%     
==========================================
  Files         177      177              
  Lines        7237     7247      +10     
  Branches     1501     1505       +4     
==========================================
+ Hits         5604     5607       +3     
  Misses        162      162              
- Partials     1471     1478       +7     

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