Add support for different types of reports coming from Reporting API

[olksdr]

Currently Relay supports NEL and CSP report types which can come from Reporting API.

But there are few more which Relay could support.

Also, the next type of report, which is interesting for our users can be crash, which is emitted when the browser crashes while your site is open.

The idea is to add a general ingest endpoint, where any (different) kind of report types can be submitted. In the beginning Relay also can decide which one we want to forward to Sentry and which one will be filtered out.