Bugfix: Add default username and password for etcd coordinator

[aolfat]

Description

Coordinator has no etcd username and password set which makes it so that the runners can't access etcd

Type of change

Does this correspond to an open issue?

Select type(s) of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have fixed any merge conflicts

[codecov]

Codecov Report

Merging #798 (2931be4) into main (6f7b498) will decrease coverage by 2.86%.
The diff coverage is 59.09%.

@@            Coverage Diff             @@
##             main     #798      +/-   ##
==========================================
- Coverage   59.71%   56.85%   -2.86%     
==========================================
  Files          63       66       +3     
  Lines       12408    12974     +566     
==========================================
- Hits         7409     7376      -33     
- Misses       4232     4883     +651     
+ Partials      767      715      -52     

Impacted Files	Coverage Δ
helpers/compression/compression.go	0.00% <0.00%> (ø)
provider/filestore.go	25.54% <ø> (-17.39%)	⬇️
provider/k8s.go	9.30% <ø> (-20.90%)	⬇️
provider/provider_config/spark_config.go	60.60% <ø> (+3.55%)	⬆️
provider/provider_type/provider_type.go	100.00% <ø> (ø)
provider/redshift.go	85.24% <ø> (ø)
provider/spark.go	23.25% <ø> (+4.67%)	⬆️
provider/sql.go	65.47% <ø> (-0.31%)	⬇️
runner/worker/worker.go	78.57% <ø> (ø)
serving/serialize.go	74.81% <ø> (-19.58%)	⬇️
... and 7 more

... and 14 files with indirect coverage changes

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[ahmadnazeri]

LGTM with just one question