Support filter for /events API endpoint

[alexluong]

Users need the ability to filter events and deliveries by various criteria such as HTTP status code, delivery status, time ranges, or custom attributes.

[leaanthony-sc]

Dupe of #492 ?

[alexbouchardd]

Not a dupe, I believe this relates to the /events API filter and #492 refers to destination filters (filtering events sent to the destination)

[leggetter]

Not a dupe, I believe this relates to the /events API filter and #492 refers to destination filters (filtering events sent to the destination)

@alexluong worth clarifying in the title and description?

[alexluong]

@leggetter updated!