OTLPReceiver is with config private, it needs to be public for create from other packages

[lpegoraro]

Describe the bug
The httpServerSettings from otlpreceiver.config.go needs to be public,

Steps to reproduce
NA

What did you expect to see?

type HttpServerSettings struct {
   *confighttp.HTTPServerSettings `mapstructure:",squash"`

   // The URL path to receive traces on. If omitted "/v1/traces" will be used.
   TracesURLPath string `mapstructure:"traces_url_path,omitempty"`

   // The URL path to receive metrics on. If omitted "/v1/metrics" will be used.
   MetricsURLPath string `mapstructure:"metrics_url_path,omitempty"`

   // The URL path to receive logs on. If omitted "/v1/logs" will be used.
   LogsURLPath string `mapstructure:"logs_url_path,omitempty"`
}

What did you see instead?

type httpServerSettings struct {
   *confighttp.HTTPServerSettings `mapstructure:",squash"`

   // The URL path to receive traces on. If omitted "/v1/traces" will be used.
   TracesURLPath string `mapstructure:"traces_url_path,omitempty"`

   // The URL path to receive metrics on. If omitted "/v1/metrics" will be used.
   MetricsURLPath string `mapstructure:"metrics_url_path,omitempty"`

   // The URL path to receive logs on. If omitted "/v1/logs" will be used.
   LogsURLPath string `mapstructure:"logs_url_path,omitempty"`
}

What version did you use?
0.82.0

What config did you use?
N/A

Environment
N/A

Additional context
No additional context