feat: Add finish action options for installation

[Itxaka]

• Introduced options for actions after installation: reboot, poweroff, or none.
• Updated UI to allow users to select their preferred action upon completion.
• Enhanced configuration handling to support new finish action settings.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 43 lines in your changes missing coverage. Please review.
✅ Project coverage is 42.83%. Comparing base (e688455) to head (8b84a05).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/agent/TUIinstallOptionsPage.go	0.00%	36 Missing ⚠️
internal/agent/config.go	0.00%	6 Missing ⚠️
internal/agent/TUIsummaryPage.go	0.00%	1 Missing ⚠️

❌ Your project status has failed because the head coverage (59.99%) is below the target coverage (60.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1004      +/-   ##
==========================================
- Coverage   43.12%   42.83%   -0.30%     
==========================================
  Files          60       60              
  Lines        7735     7772      +37     
==========================================
- Hits         3336     3329       -7     
- Misses       4074     4116      +42     
- Partials      325      327       +2     

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[mudler]

love it!