feat: support zk log options & flags fix

[vagetablechicken]

Closes #1500
CLI: disable zk log by default(log level 0). use gflags zk_log_level & zk_log_file to modify ClusterOptions.
other sdk: use default ClusterOptions now, info level and use stream stderr(default in zk).

make more flag desc.

[codecov]

Codecov Report

Merging #1938 (b5ef04a) into main (6525d83) will decrease coverage by 0.14%.
The diff coverage is 68.18%.

@@             Coverage Diff              @@
##               main    #1938      +/-   ##
============================================
- Coverage     75.77%   75.62%   -0.15%     
  Complexity      347      347              
============================================
  Files           613      614       +1     
  Lines        117624   116976     -648     
  Branches       1025     1025              
============================================
- Hits          89125    88463     -662     
- Misses        28290    28304      +14     
  Partials        209      209              

Impacted Files	Coverage Δ
src/cmd/sql_cmd.h	26.71% <0.00%> (-0.63%)	⬇️
src/zk/zk_client.h	100.00% <ø> (ø)
src/zk/zk_client.cc	83.37% <66.66%> (-0.18%)	⬇️
src/sdk/db_sdk.cc	66.59% <80.00%> (+2.64%)	⬆️
src/sdk/db_sdk.h	92.50% <100.00%> (+1.07%)	⬆️
src/storage/schema.h	84.55% <0.00%> (-4.88%)	⬇️
src/storage/schema.cc	77.43% <0.00%> (-4.27%)	⬇️
src/rpc/rpc_client.h	89.18% <0.00%> (-1.36%)	⬇️
src/nameserver/name_server_test.cc	91.81% <0.00%> (-0.47%)	⬇️
src/catalog/client_manager.cc	42.20% <0.00%> (-0.29%)	⬇️
... and 30 more

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[github-actions]

SDK Test Report

  75 files    75 suites   5m 16s ⏱️
163 tests 161 ✔️ 2 💤 0 ❌
204 runs  202 ✔️ 2 💤 0 ❌

Results for commit b5ef04a.

♻️ This comment has been updated with latest results.

[github-actions]

Linux Test Report

       57 files       196 suites   51m 45s ⏱️
  8 941 tests   8 937 ✔️ 4 💤 0 ❌
13 157 runs  13 153 ✔️ 4 💤 0 ❌

Results for commit b5ef04a.

♻️ This comment has been updated with latest results.

[tobegit3hub]

LGTM