clean code for isBlank

fix table case

fix schema

add default email for apollo user

support user email field

return users when search user keyword is empty

fix for spring security auth table case issue

fix potential conditional npe

support spring security auth

Add ConditionalOnProfile and ConditionalOnMissingProfile annotations

Config service cache and namespace name normalization

1. Enable config cache to improve config service performance, just set
config-service.cache.enabled to true in ServerConfig
2. Normalize the namespace name in case the one provided has character
case issue

output ClassLoaderUtil exception to logger

Update CatEventType to TracerEventType