[REFACTOR] consolidate service configuration objects

[james-milligan]

Requirements

Currently the flagd ConnectServer handles 2 separate configuration objects:
Configuration

type Configuration struct {
	ReadinessProbe ReadinessProbe
}

and
ConnectServiceConfiguration

type ConnectServiceConfiguration struct {
	Port             int32
	MetricsPort      int32
	ServerCertPath   string
	ServerKeyPath    string
	ServerSocketPath string
	CORS             []string
}

These should be consolidated into a single configuration object, and passed / set to the ConnectService in a. single action.
Currently ConnectServiceConfiguration is set on struct instantiation, with Configuration being passed in the Serve method:

Serve(ctx context.Context, eval eval.IEvaluator, svcConf Configuration) error

IMO the ConnectServiceConfiguration object should be merged into Configuration and passed to flagd via the Serve method, as this gives a cleaner interface + standardised type across future services

[odubajDT]

Hey, I would like to pick this issue