drop MemberClusterService interface & rename the implementation

[MatousJobanek]

• drop MemberClusterService interface
• rename the implementation to MemberClusters
• move it to the proxy package
• provide the GetMemberClustersFunc as a parameter, so it uses the same as is used in proxy.go
  • this also slightly simplifies the tests
• drop "ServiceImpl options" as they are not needed anymore
• drop ProxyFakeApp as it is not needed anymore

KUBESAW-237

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.46%. Comparing base (738daee) to head (17a3ed7).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #483      +/-   ##
==========================================
+ Coverage   85.35%   85.46%   +0.11%     
==========================================
  Files          32       32              
  Lines        3175     3172       -3     
==========================================
+ Hits         2710     2711       +1     
+ Misses        378      374       -4     
  Partials       87       87              

Flag	Coverage Δ
unittests	85.46% <100.00%> (+0.11%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

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

[mfrancisc]

Really nice simplification 👍

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alexeykazakov, MatousJobanek, mfrancisc

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [MatousJobanek,alexeykazakov,mfrancisc]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[sonarqubecloud]

Quality Gate passed

Issues
17 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
15.7% Duplication on New Code

See analysis details on SonarQube Cloud