Refactor optimizer

Support build index with multiple gpu and update config

[skip ci] Change ivfsq8 test report detailed version #255

Add a Fallback pass in optimizer close #409

add Fallback pass condition

Fix Deployed GPU-version docker failed in CI

Add virtual method Init() in Pass abstract class close #404

[skip ci] Add note about using unbuntu docker

[skip ci] Change ivfsq8 test report detailed version #255

#397 sdk_simple return incorrect result

update add configurable DB settings

fix by reduce knng size

remove gpu in db unittest

#266 Rpc request source code refactor

Update nightly-build config