Add support for translations / internationalization / localization of page elements

[choldgraf]

When people build HTML outputs with mystjs, there are many labels, titles, tooltips, etc that are hard-coded in English. For communities that wish to use this tool for non-English speakers, they need the ability to display these elements in the language of their choice.

This could be done by having a translation bank in this project, and the ability for users to trigger certain languages in their configuration. It could also be done by giving users the ability to define their own translated phrases and insert them into the outputs.

I know this is likely a large effort with many under-the-hood changes, so consider this a "long term tracking issue" to note that we need to do it as some point, and to track down the work over time.

[mmcky]

QuantEcon is currently undertaking a project assessing how AI can be used to assist with translations to other languages. We are exploring a range of tooling including ChatGPT, various OpenAI models, and service layers such as crowdin which has support for open-source projects.

Our vision is to develop an open-source compatible workflow that uses AI to get to the 90% mark in the translation, leaving the last 10% to human proof-reading and updates. This is the approach we are taking in our first translation project of the introductory lecture series

There are various technical aspects to this project in the medium to longer term including:

1. How to enable good version control of source material in multiple languages. It would be nice to have tooling that allows for better line-by-line level control in the translation process for bi-directional updates from, for example, English -> Chinese, or from Chinese -> English. There may not always be a single source of truth in future projects, so bi-directional updating would be really useful.
2. Enabling an interface that allows reader feedback to improve translations (that isn't a pull request)