feat: add support for custom tooling image

[sozercan]

Describe the changes in this pull request using active verbs such as Add, Remove, Replace ...

Closes #329

[codecov]

Codecov Report

Attention: 10 lines in your changes are missing coverage. Please review.

Comparison is base (e8b5e13) 31.93% compared to head (e7bf564) 32.12%.
Report is 10 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #330      +/-   ##
==========================================
+ Coverage   31.93%   32.12%   +0.18%     
==========================================
  Files          18       18              
  Lines        1622     1628       +6     
==========================================
+ Hits          518      523       +5     
- Misses       1073     1074       +1     
  Partials       31       31              

Files	Coverage Δ
pkg/pkgmgr/pkgmgr.go	12.98% <ø> (ø)
pkg/patch/cmd.go	48.88% <50.00%> (+0.05%)	⬆️
pkg/pkgmgr/apk.go	51.49% <0.00%> (ø)
pkg/pkgmgr/dpkg.go	35.33% <66.66%> (+0.69%)	⬆️
pkg/pkgmgr/rpm.go	33.93% <66.66%> (+0.17%)	⬆️
pkg/patch/patch.go	6.36% <0.00%> (ø)

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[sozercan]

closing in favor of #341