Allow manipulating events in RES browser

[tomaszwro]

• link an event to a stream
• unlink an event from a stream 🙀
• filter events by type and/or attributes and allow bulk-adding to a stream
• and even worse things, which it's indecent to talk about
• instead of writing it to the DB, probably the tool can spit out ruby code to paste into a migration, commit and push

[tomaszwro]

• dumping an event from the browser into a fixture