Allow to start wallet API by cashu --daemon

[sihamon]

Closes #202

[codecov]

Codecov Report

Patch coverage: 68.75% and project coverage change: -0.51 ⚠️

Comparison is base (08ceeda) 56.06% compared to head (1fe1875) 55.56%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #243      +/-   ##
==========================================
- Coverage   56.06%   55.56%   -0.51%     
==========================================
  Files          42       42              
  Lines        3328     3324       -4     
==========================================
- Hits         1866     1847      -19     
- Misses       1462     1477      +15     

Impacted Files	Coverage Δ
cashu/wallet/api/api_server.py	50.00% <50.00%> (ø)
cashu/wallet/cli/cli.py	48.26% <71.42%> (+0.47%)	⬆️
cashu/core/settings.py	97.43% <100.00%> (+0.06%)	⬆️
cashu/wallet/api/router.py	76.08% <100.00%> (+6.23%)	⬆️

... and 5 files with indirect coverage changes

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[callebtc]

Test failing for inexplicable reasons.