Spell CloudEvents Uniformly

[grant]

In this repo, it appears we have multiple spellings of the term CloudEvent, in particular with TypeScript filenames:

• CloudEvent.ts
• cloud_events.ts
• CloudEvents.ts
• cloudevent.ts

Ideally, these spellings should be uniform within the repo. Having the spelling uniform across the FFs (but idiomatic to the language) would be great too.