Reduce etcd server memory usage

[samutamm]

• set snapshot count to lower value to reduce etcd ram usage https://etcd.io/docs/v3.5/tuning/#snapshot-tuning
• fix etcd_client.log is too verbal #420 ; do not print debug client logs if --debug flag is not provided for server

[codecov-commenter]

Codecov Report

Merging #439 (85cf299) into main (fb7d28c) will decrease coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #439      +/-   ##
==========================================
- Coverage   80.44%   80.41%   -0.04%     
==========================================
  Files          70       70              
  Lines        8094     8096       +2     
==========================================
- Hits         6511     6510       -1     
- Misses       1225     1226       +1     
- Partials      358      360       +2     

Impacted Files	Coverage Δ
pkg/cluster/config.go	89.07% <100.00%> (+0.18%)	⬆️
pkg/object/mqttproxy/client.go	78.60% <0.00%> (-1.40%)	⬇️

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[suchen-sci]

@samutamm please update httpserver_test.sh to solve conflicts...

[samutamm]

@samutamm please update httpserver_test.sh to solve conflicts...

@suchen-sci conflicts resolved