support for equivalent of `disableSend` and `contextPropagationOnly`; central config `send_traces`, `send_metrics`, `send_logs`

[trentm]

1. The classic agent has the related disableSend and contextPropagationOnly config options. Let's add support for equivalents to EDOT Node.js. (FWIW, EDOT Java has done the same. See [Config] Add Disable Send and Context Propagation Only elastic-otel-java#304 and https://github.com/elastic/elastic-otel-java/pull/474/files#diff-9492e17b995ca3fa70c6000d6dd033dd2d2b71781abafd4e1f130f61a97f5047R82-R94)
2. Let's also implement central config send_traces, send_metrics, send_logs settings -- a subset of the settings we are trying to make common across EDOT SDKs.