Consider turning on caching for `Guide` object

This is a reminder to reconsider turning on caching for the guide, which was turned off due to pickling issues of python bindings provided by `outlines-core`: https://github.com/dottxt-ai/outlines/pull/1278

Most likely this will be done after this issue: https://github.com/dottxt-ai/outlines-core/issues/95