Fixes#2876 with @paulmelnikow's suggestion
Moved imports of `ServiceTester` and `createServiceTester` to a separate file so that dev dependencies are not imported by service classes.
Continue to implement #2698:
- Add `core/base-service/index.js` (but hold off on moving the things it imports)
- Add shortcuts in `services/index.js` for Base*Service, errors, and deprecatedService. This file will be streamlined later to avoid cluttering it with rarely used bits.
- Apply consistent ordering of imports and use of `module.exports` in testers.
- Remove some renaming of imports.
- Remove obsolete tests here and there.
Close#2334
To avoid merge conflicts, I've deferred removing the aliasing logic in `prepareExamples`. That whole function will be refactored momentarily, and there's also #2339 open.
The term “url” is overloaded in services, to refer to the Shields route and also the API URL. Calling the Shields URL a “route” is on the whole more descriptive, and makes it clearer and more obvious which one of these we’re talking about. It’s a small thing, though seems like an improvement.
We have a few functions called `buildUrl`. I’ve renamed them to `buildRoute` when they refer to routes, and left them as `buildUrl` when they refer to API URLs.
I included a minor style tweak and some formatting cleanup in `TUTORIAL.md`.
all-badge-examples is a common cause of merge conflicts. It’s difficult to adjust the badge categorization in that file – or to understand the diff – because it requires moving a block from one point to another. It’s much easier to edit a badge’s category in one place.
This starts the process of breaking up what’s left of that file, following up on the work from #1931. New-style services can only be in one category, which means legacy service examples have to be split along category lines. I split out separate legacy service classes where I could do so easily, leaving behind the ones which require more work, for one reason or another.
