feat: Wrappers for Consistent Response Formatting in GEM

[N00bcak]

tl;dr

Add a EncapsulateWrapper to detect and enforce common response signposts used by LLMs (like \boxed{} and <answer></answer>)

Motivation

Currently GEM as a library appears somewhat undecided about how to extract unambiguous answers from LLMs. QAEnv uses <answer> HTML tags while the TextArena environments appear to use \boxed{} TeX tags.

Since they are currently baked into the environment, the environments themselves can become more difficult to use if a different tagging convention is desired (either due to language model constraints/quirks, or experimental consistency).

Taking into account this potential diversity of tagging conventions, this PR hopes to offer a potential direction forward for decoupling action extraction from action handling within GEM environments, to make sure environments can be useful to a wider audience and to reduce implementation complexity (because now environments no longer need to assume a certain kind of tagging format)

Word of Caution

Despite this PR pointing out the inconsistencies in GEM's response tagging and extraction, no real changes have yet been made to existing/in-development environments, their prompts, or their action parsing procedures.

These are breaking changes which may affect experimental results (due to differences in prompting), and I am currently looking for ways to resolve this with minimal impact.