Add server name TLS option to OTLP exporter (#1203)

Author: dhurley

internal/collector/otelcol.tmpl

@@ -182,6 +182,7 @@ exporters:
       {{ if gt (len .TLS.Ca) 0 -}}ca_file: "{{- .TLS.Ca -}}"{{- end }}
       {{ if gt (len .TLS.Cert) 0 -}}cert_file: "{{- .TLS.Cert -}}"{{- end }}
       {{ if gt (len .TLS.Key) 0 -}}key_file: "{{- .TLS.Key -}}"{{- end }}
+      {{ if gt (len .TLS.ServerName) 0 -}}server_name_override: "{{- .TLS.ServerName -}}"{{- end }}
       {{- end }}
     {{- if .Authenticator }}
     auth: