refactor(artifact): refactoring scan and tag subcommands under artifacts

[NucleoFusion]

The current structure has the scan and tags subcommand under the artifact root command in one singular file and not the correct file structure

[codecov]

Codecov Report

❌ Patch coverage is 0% with 149 lines in your changes missing coverage. Please review.
✅ Project coverage is 7.45%. Comparing base (60ad0bd) to head (e9f511c).
⚠️ Report is 105 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/harbor/root/artifact/tags/list.go	0.00%	33 Missing ⚠️
cmd/harbor/root/artifact/tags/create.go	0.00%	26 Missing ⚠️
cmd/harbor/root/artifact/tags/delete.go	0.00%	26 Missing ⚠️
cmd/harbor/root/artifact/scan/scan.go	0.00%	21 Missing ⚠️
cmd/harbor/root/artifact/scan/start.go	0.00%	15 Missing ⚠️
cmd/harbor/root/artifact/scan/stop.go	0.00%	15 Missing ⚠️
cmd/harbor/root/artifact/tags/tags.go	0.00%	11 Missing ⚠️
cmd/harbor/root/artifact/cmd.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             main    #700      +/-   ##
=========================================
- Coverage   10.99%   7.45%   -3.54%     
=========================================
  Files         173     266      +93     
  Lines        8671   12924    +4253     
=========================================
+ Hits          953     964      +11     
- Misses       7612   11851    +4239     
- Partials      106     109       +3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[qcserestipy]

LGTM

[bupd]

/lgtm

[bupd]

@NucleoFusion please check and fix the lint issues - https://github.com/goharbor/harbor-cli/actions/runs/22627389260/attempts/1#summary-65567647631

Thanks for the contribution.

[NucleoFusion]

@bupd solved!