ref(node-experimental): Remove custom hub & scope

[mydea]

This removes almost all the custom hub & scope stuff from node-experimental/opentelemetry!

1. I opted to leave the setupGlobalHub() method in as a noop, as that is currently documented for @sentry/opentelemetry. We can't deprecate this on v7 as it is required there... but it's OK imho, it's just an empty function we can remove in v9.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser (incl. Tracing, Replay, Feedback) - Webpack (gzipped)	77.84 KB (-0.07% 🔽)
@sentry/browser (incl. Tracing, Replay) - Webpack (gzipped)	69.08 KB (-0.07% 🔽)
@sentry/browser (incl. Tracing, Replay with Canvas) - Webpack (gzipped)	73 KB (-0.07% 🔽)
@sentry/browser (incl. Tracing, Replay) - Webpack with treeshaking flags (gzipped)	62.69 KB (-0.07% 🔽)
@sentry/browser (incl. Tracing) - Webpack (gzipped)	33.28 KB (-0.09% 🔽)
@sentry/browser (incl. browserTracingIntegration) - Webpack (gzipped)	33.13 KB (-0.09% 🔽)
@sentry/browser (incl. Feedback) - Webpack (gzipped)	31.13 KB (-0.1% 🔽)
@sentry/browser (incl. sendFeedback) - Webpack (gzipped)	31.13 KB (-0.1% 🔽)
@sentry/browser - Webpack (gzipped)	22.41 KB (-0.13% 🔽)
@sentry/browser (incl. Tracing, Replay, Feedback) - ES6 CDN Bundle (gzipped)	75.81 KB (-0.09% 🔽)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (gzipped)	67.37 KB (-0.1% 🔽)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (gzipped)	33.33 KB (-0.14% 🔽)
@sentry/browser - ES6 CDN Bundle (gzipped)	24.43 KB (-0.21% 🔽)
@sentry/browser (incl. Tracing, Replay) - ES6 CDN Bundle (minified & uncompressed)	212.34 KB (-0.13% 🔽)
@sentry/browser (incl. Tracing) - ES6 CDN Bundle (minified & uncompressed)	100.97 KB (-0.2% 🔽)
@sentry/browser - ES6 CDN Bundle (minified & uncompressed)	73.38 KB (-0.27% 🔽)
@sentry/browser (incl. Tracing) - ES5 CDN Bundle (gzipped)	36.56 KB (-0.18% 🔽)
@sentry/react (incl. Tracing, Replay) - Webpack (gzipped)	69.44 KB (-0.08% 🔽)
@sentry/react - Webpack (gzipped)	22.44 KB (-0.13% 🔽)
@sentry/nextjs Client (incl. Tracing, Replay) - Webpack (gzipped)	87.26 KB (-0.07% 🔽)
@sentry/nextjs Client - Webpack (gzipped)	50.38 KB (-0.07% 🔽)
@sentry-internal/feedback - Webpack (gzipped)	17.1 KB (-0.03% 🔽)