Step Ids and step file names did not follow a consistent pattern. To make it easier to automate in the future, things were renamed in the following ways:

StepId: camel case, prefix with the short name that we usually use to refer to the tutorial, e.g. name, music, chaseGame. Followed by a name for the step, e.g. nameAddSprite, nameAddBackdrop. When there are two of a step, add ‘2’ to the end e.g. nameAddSprite2

file-naming: all step files should be in the steps directory. The name is the ‘kebab’ case of the stepId, followed by the language-code, then the file extension. For example the english version of the file for `nameAddSprite` would be `name-add-sprite.en.gif`, `chaseGameAddSprite2` would be `chase-game-add-sprite2.en.gif`

* thumbnails folder: thumbnail images for tutorials (multistep decks and videos). Images should not need translations (avoid text that would need translation in the image)
* steps folder: gif images associated with tutorial steps. Images can be translated. English (default) images have the extension `.en.gif`, other language images should replace the `.en` with the corresponding locale.
* renamed some of the steps files to be more consistent and a bit less redundant
* removed a couple of files that were no longer referenced
* revised webpack config to allow localized step files to be loaded from `/static` on www

Extracting the drawable art data is very expensive. We should delay
doing that work as long as possible. As such it should wait until a few
more branching return statements before we extract it.

Because the `onFrame` callback could do async work, it was possible for onDone to try to submit the costumes before the onFrame had produced any. This was subject to browsers different timing treatments of setTimeout vs. promise resolution. This makes the gif-decoder use the same style of progress API as the file uploader

Fixes #4253 by telling the vm the langauge when it is initialized.  Before it didn't get the language until the blocks component mounted.

Selenium loads the playground using the file:// protocol, where history.replaceState throws an error

This only shows when you are on a project that is SHOWING_WITHOUT_ID and has changes. This is only the case when logged out, or in the desktop editor.

Proof of concept with spanish as the only example.

This was already being used for sb3s and sprite3s, but the code was repeated in different places. Make a single helper that downloads blobs, and make all download paths use it.

I needed to update the player css because the editor side wasn't large enough to be useable.