Allow specifying a timestamp when creating Events

[mayurkale22]

Based on the issue: #213

The spec defines an Event as follows:

A Span MUST have the ability to add events. Events have a time associated with the moment when they are added to the Span.

Please update the API and corresponding SDK implementation(s).

opentelemetry-js/packages/opentelemetry-types/src/trace/span.ts

Lines 59 to 66 in 17690e6

	/**
	* Adds an event to the Span.
	*
	* @param name the name of the event.
	* @param [attributes] the attributes that will be added; these are
	* associated with this event.
	*/
	addEvent(name: string, attributes?: Attributes): this;

[obecny]

@mayurkale22 would that make sense if I take it and make necessary changes so that I can finish the document-load plugin by adding time for events as discussed with @draffensperger in PR #433 ?

[mayurkale22]

Sure, I have assigned to you. Thank you 😊