feat: streaming events and errors

[adrums86]

Description

Adding some additional events and errors with relevant payloads to VHS to enable users to centralize streaming events and utilize the information passed with each error and event payload to inform their video playback code.

Specific Changes proposed

Add events and payloads for all phases of playback from manifest/playlist request - load - parse. Segment load - transmux/parse/decrypt - append. Errors and relevant payloads for common network, segment and playlist/manifest conditions.

Requirements Checklist

• [x] Feature implemented / Bug fixed
• [x] If necessary, more likely in a feature request than a bug fix
  • [x] Unit Tests updated or fixed
  • [ ] Docs/guides updated
  • [ ] Example created (starter template on JSBin)
• [ ] Reviewed by Two Core Contributors