Add "transforming telemetry" section to collector docs

[smithclay]

Have recently received feedback from several new collector users around usability of docs in the various processors in collector-contrib. Specifically, it's difficult to know where to start for some very simple (and common) use cases like adding an attribute to a span or filtering based on service name.

This PR proposes a new section under the collector docs called "Transforming telemetry" that documents some simple examples/use-cases and links to processors for more information.

Goal of the doc isn't to exhaustively document all configurations or duplicate what is already in the contrib repo, but to provide a friendly "new to collector processors" introduction to users with some simple examples before pointing to the contrib repo for more information.

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Preview: https://deploy-preview-2304--opentelemetry.netlify.app/docs/collector/transforming-telemetry/

[svrnm]

Great addition, thank you for bringing this forward!

A few remarks, please also make sure that you run prettier over your file so that the formatting is correct.

[mviitane]

This page seems a great addition overall! Added just one minor comment.

[smithclay]

Thanks for the feedback, all! Have addressed/resolved all comments.

[chalin]

Getting closer! You'll need to rebase, run npm run check:formatting -- --write, and push changes. Thanks.

[smithclay]

• rebased
• ran npm run check:formatting -- --write

thanks, @chalin!

[chalin]

Weight change, otherwise LGTM.

[cartermp]

Great content! Exactly the kind of content with examples we need for this area of collector docs.

[svrnm]

Great content! Exactly the kind of content with examples we need for this area of collector docs.

💯

Awesome work @smithclay !!