config: add support for additional attributes

[codeboten]

The Resource model only supports a ServiceName attribute.

opentelemetry-go-contrib/config/generated_config.go

Lines 19 to 22 in 044e09a

	type Attributes struct {
	// ServiceName corresponds to the JSON schema field "service.name".
	ServiceName *string `mapstructure:"service.name,omitempty"`
	}

This should be updated to support additional attributes as pointed out by @pellared here: #4824 (comment)

[codeboten]

please assign to me :)

[AkhigbeEromo]

Hello @pellared @codeboten i wanted to ask if this issue has already been solved and if it has not what other attributes would you like to be added. i am also open to work on this issue