`handlers.llm.sampling` should be moved to an example ahead of initial release

[eb8680]

Before we land #363 on master we should temporarily move handlers/llm/sampling.py out of the library code and inline it into a relevant example's code (e.g. the original source #404). While at a high level we will certainly want machinery like this in the library, the design and implementation are likely to change significantly in the near term (cf #415 #417 #407 etc) so we probably don't want to commit to maintaining it in its current form.

[jfeser]

@kiranandcode Do you want to fold this code back into #404? If that example is close to being finished, we could try to land the whole branch.

[kiranandcode]

Oh yep, that would work, though Im currently in the UK and its 8pm @jfeser so the earliest I can get to it is tomorrow so if its a blocker then it might be a separate PR

[jfeser]

No rush! If you're busy, let me know and I'll pick it up tomorrow.