Event Publishing Be An Array Endpoint

[hannahhoward]

Goal

Building on #112 and in conjunction with filecoin-project/tornado-deploy#8, let's make the retrieval events posting api accept an array of events, instead of a single event. Based on the architecture of #112, it should be possible to just make the reportChan on the event recorder an array of reports, and then in the ingestReports go routine just forward the whole array of queued events rather than a single event.

We'll need to figure out timing so we can launch this at the same time as filecoin-project/tornado-deploy#8

[kylehuntsman]

The API could accept both formats as a compatibility thing, and then we would just need the API to be deployed prior to the client update.