Adds support for logs (specify level), metrics (enable metrics and Prometheus /metrics endpoint
and traces (jaeger or otlp) for standalone API server. This will allow any grafana core service
part of standalone apiserver to use logging, metrics and traces as normal.
This is preparative work for extending the grafana server cli command to target individual dskit modules that seemed worth breaking into this smaller PR. This moves the CLI flags and various reusable chunks of code into variables and methods.
