Delete aframe.js (ancient & unused copy of code from 0.4.0)

[diarmidmackenzie]

Following on from aframevr/aframe#5333 and based on comments from @vincentfretin, I checked aframe-inspector for any usage of 'https://cdn.aframe.io'.

The only instances I found were in the module examples\js\aframe.js.

This appears to be a copy of the 0.4.0 distribution of A-Frame, and not used by any of the examples. I believe it can be deleted, and it would be good housekeeping to do so.

Hence this PR.

[vincentfretin]

Yes indeed.

[vincentfretin]

The list of textures images I talked about in comment aframevr/aframe#5119 (comment) is retrieved via https://aframe.io/sample-assets/dist/images.json when you open the texture modal.
The url is defined here

aframe-inspector/src/lib/assetsLoader.js

Line 3 in 72fd461

const assetsBaseUrl = 'https://aframe.io/sample-assets/';

but that's different from https://cdn.aframe.io/ so you can't use AFRAME_ROOT_CDN here. If we introduce another configurable constant, that can be done in another PR. But also this feature should maybe be dropped completely, see #676

[vincentfretin]

For my comment above, I created #702

@dmarcos this PR just remove an unused file, you can merge.

[dmarcos]

Thanks!