Pass exporter identifier to http client metrics

[harsh8398]

Is your feature request related to a problem? Please describe.
Currently, it is impossible to identify what exporter is emitting the detailed http instrumentation metrics listed here. This is especially a prominent problem when trying to debug issues in systems using many types of exporters.

Describe the solution you'd like
Add exporter identifier to all http instrumentation metrics

Additional context

Example metric showing current available attributes:

# HELP otelcol_http_client_duration Measures the duration of outbound HTTP requests.
# TYPE otelcol_http_client_duration histogram
otelcol_http_client_duration_bucket{http_method="POST",http_status_code="401",net_peer_name="xyz",service_instance_id="142ba07c-ca3e-4ede-8fd6-de3e18a347e0",service_name="otelcorecol",service_version="0.103.0-dev",le="0"} 0