Onboarding new Wikipedians/Revision tag

This document describes the revision tags adding to edits by users of the GettingStarted extension, as part of the new editor onboarding process.

Rationale
We apply revision tags to these edits to fulfill several use cases, captured in the following user stories: To summarize, the revision tags provide transparency in to use of the GettingStarted features, while also provide us an analytical tool.
 * As a Wikipedian, I want to know how a new user found a particular page and why they're editing it.
 * As a Wikipedian, I want to have access to a stream of all edits made via GettingStarted suggestions, so I can check them for quality.
 * As one of the maintainers of the GettingStarted extension, I want to have an easy way to track all edits made through GettingStarted, so that I can understand the impact it's having on a wiki.

Specification
This is how revision tagging will work.

Current
The current revision tag text -- Tag: new editor getting started -- is applied to revisions that result from the Special:GettingStarted landing page and where the user still has the GettingStarted toolbar. (See a list of GettingStarted edits on English Wikipedia). If the user edits any other page or closes the toolbar on a relevant task page, the edits are no longer tagged.

New
The new behavior is that we apply the edit tag to all edits made to suggested pages by users who accepted our calls-to-action. If I am redirected to a page I'm interested in and edit via the guided tour, all my further edits to that page are tagged. The same goes for edits to random suggested pages.

Since the new text may not precisely refer to a brand-new editor, we're revising the tag text. It now will read as "Tag: via Getting Started edit suggestions"