feat: member clusters can join the control cluster through token

[codecov[bot]]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (bd2d0f4) 30.21% compared to head (e2077d7) 30.39%.

Files	Patch %	Lines
pkg/util/cluster/client.go	86.95%	3 Missing :warning:
pkg/controllers/federatedcluster/controller.go	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #292 +/- ## ========================================== + Coverage 30.21% 30.39% +0.17% ========================================== Files 120 120 Lines 13952 13944 -8 ========================================== + Hits 4216 4238 +22 + Misses 9330 9301 -29 + Partials 406 405 -1 ``` | [Flag](https://app.codecov.io/gh/kubewharf/kubeadmiral/pull/292/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=kubewharf) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/kubewharf/kubeadmiral/pull/292/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=kubewharf) | `30.39% <83.33%> (+0.17%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=kubewharf#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.