feat: imporve cluster register and addon

[yipeng1030]

partly fixed: #420

what's changed:

1. Cluster register supports overriding the built-in chart, pulling by helm repo + engine + version, and validating schema standards.
2. Addon install and search support specifying a local path.
3. Addon install, enable, and upgrade support register the chart at the same time.
4. Addon uninstall also deletes the corresponding chart.
5. Addon search supports searching for all addons (including those not installed).

[codecov-commenter]

Codecov Report

❌ Patch coverage is 46.34921% with 169 lines in your changes missing coverage. Please review.
✅ Project coverage is 43.54%. Comparing base (55f8f45) to head (1f1ab2e).
⚠️ Report is 117 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/cluster/external_charts.go	17.85%	46 Missing ⚠️
pkg/cmd/addon/util.go	32.20%	40 Missing ⚠️
pkg/cmd/cluster/register.go	57.35%	19 Missing and 10 partials ⚠️
pkg/cmd/addon/search.go	76.00%	13 Missing and 5 partials ⚠️
pkg/util/helm/helm.go	0.00%	16 Missing ⚠️
pkg/cmd/addon/install.go	54.83%	11 Missing and 3 partials ⚠️
pkg/cmd/addon/upgrade.go	50.00%	3 Missing ⚠️
pkg/cmd/addon/uninstall.go	0.00%	2 Missing ⚠️
pkg/cmd/addon/addon.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #442      +/-   ##
==========================================
+ Coverage   43.39%   43.54%   +0.14%     
==========================================
  Files         174      174              
  Lines       24500    24710     +210     
==========================================
+ Hits        10632    10760     +128     
- Misses      12637    12707      +70     
- Partials     1231     1243      +12     

Flag	Coverage Δ
unittests	43.54% <46.34%> (+0.14%)	⬆️

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