refactor: separate cluster connect cmd from its implementation logic

[shawnh2]

separate gtctl cmd from its implementation logic, this PR only separate cluster connect cmd.

others will be done in the following PRs.

related to: #160

[codecov-commenter]

Codecov Report

Attention: 39 lines in your changes are missing coverage. Please review.

Comparison is base (1452867) 34.75% compared to head (9f74e21) 35.36%.
Report is 2 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #159      +/-   ##
===========================================
+ Coverage    34.75%   35.36%   +0.61%     
===========================================
  Files           10       11       +1     
  Lines         1315     1377      +62     
===========================================
+ Hits           457      487      +30     
- Misses         766      793      +27     
- Partials        92       97       +5     

Files	Coverage Δ
pkg/cmd/gtctl/cluster/create/create.go	0.00% <0.00%> (ø)
pkg/artifacts/manager.go	56.04% <20.00%> (-0.72%)	⬇️
pkg/metadata/manager.go	85.29% <85.29%> (ø)
pkg/helm/helm.go	58.47% <50.00%> (-4.03%)	⬇️
pkg/deployer/baremetal/deployer.go	30.42% <19.23%> (-0.99%)	⬇️

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

[zyy17]

IMHO, I feel that the two approaches are more about style differences, but this approach seems to separate the specific usage points of the method into cmd/gtctl, so it can look cleaner. Let's try your way.

[zyy17]

The PR title seems OK, but why the CI always failed?

[shawnh2]

The PR title seems OK, but why the CI always failed?

there is something wrong with current ci, will be fixed in #163

[zyy17]

lgtm