Add obs-websocket 5.0.0 integration

Description

This adds integration into obs-websocket's new plugin API. The vendor name registered is obs-browser.

Vendor requests:

emit_event - Takes event_name and ?event_data parameters. Emits a custom event to all browser sources.

Motivation and Context

Integration between obs-browser and obs-websocket is a great proof of concept for our API and should serve as a great example for third-party plugin developers.

How Has This Been Tested?

Tested by sending a request to obs-websocket and listening for the event in a test HTML page.

Request:

Test HTML Page:

<!DOCTYPE html>

<script type="text/javascript">
  window.addEventListener('obs-websocket-test-event', function(event) {
    console.log(event.detail)
  })
</script>

Result in dev tools:

Types of changes

New feature (non-breaking change which adds functionality)

Checklist:

[x] My code has been run through clang-format.
[x] I have read the contributing document.
[x] My code is not on the master branch.
[x] The code has been tested.
[x] All commit messages are properly formatted and commits squashed where appropriate.
[x] I have included updates to all appropriate documentation.

obsproject / obs-browser

Add obs-websocket 5.0.0 integration #340

Description

Motivation and Context

How Has This Been Tested?

Types of changes

Checklist: