feat: support all etcd client configs

[chengjoey]

What this PR does / why we need it:

support all etcd client configs

Specified Reviewers:

/assign @sfwn

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 14 lines in your changes missing coverage. Please review.

Project coverage is 19.16%. Comparing base (f3a2492) to head (3562849).
Report is 3 commits behind head on master.

Files	Patch %	Lines
providers/etcd/etcd.go	0.00%	14 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #322       +/-   ##
===========================================
- Coverage   35.54%   19.16%   -16.38%     
===========================================
  Files         110      309      +199     
  Lines        6055    13676     +7621     
===========================================
+ Hits         2152     2621      +469     
- Misses       3738    10825     +7087     
- Partials      165      230       +65     

Flag	Coverage Δ
by-github-actions	19.16% <0.00%> (?)

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

Files	Coverage Δ
providers/etcd/etcd.go	0.00% <0.00%> (ø)

... and 201 files with indirect coverage changes

[sfwn]

/approve