Implement new setup for code snippets

[arboleya]

In the past, we had a couple of issues involving code snippets:

• https://github.com/FuelLabs/fuels-ts/issues/1960

They can be missing imports, have invalid syntax, etc. We must improve our handling of these to ensure that the code chunks we provide in the docs are 100% reliable.

I outlined a proposal for it in this discussion — https://github.com/FuelLabs/fuels-ts/discussions/2159#discussioncomment-9219003.

Here's a quick PoC for it — https://github.com/arboleya/docs-widgets.

[arboleya]

Blocked by:

• https://github.com/FuelLabs/fuels-ts/issues/2712