Implement Pretranslation API

[functionzz]

Feature Summary

Implement an authenticated API endpoint which returns a Pretranslation for a given Entity and locale.
Located at /api/v2/pretranslate/?text=TEXT&locale=code.

Motivation / Use Case

We currently have existing Pretranslation functionality in Pontoon. Extending this to an API endpoint can provide easier access for external users of Pretranslation functionality.

[mathjazz]

Implement an authenticated API endpoint which returns a Pretranslation for a given Entity and locale.
Located at /api/v2/pretranslation/code/entity_id.

It would be more generally useful to have text as the input parameter:
/api/v2/pretranslate/?text=TEXT&locale=CODE

[flodolo]

It would be more generally useful to have text as the input parameter:

Absolutely. The goal is not just to pretranslate strings available in Pontoon.

I assume code stands for locale code?

[functionzz]

Yep