Init ingestion fix

Fixing a bug in init ingestion

Simple init

Allowing to skip init function arguments if they are provided as environment variables

Ingestion upon init

• Sending empty ingestion on init
• adding random delay only for connections time connected < 1 min

Code coverage

Code coverage improvements and bug fix

Types for logging

• logLevel is typed now

Always cast id to string

Both entity.id and group.id are casted to string

SSE fix

• fixing a bug in sse and improving logging
• flagger is no longer a singleton, default instance is exported for backward compatibility
• LogLevel is exported

Ingestion onboarding improvements

• First 10 exposures trigger ingestion request
• Detected flag triggers ingestion request
• Tests don't hit network anymore

Exporting Reason

Exporting Reason from Core

Fix shutdown and other small fixes

Fix shutdown() and isConfigured() methods.
Do not trigger flaggerConfigUpdate event if new config is the same as the current one.