feat(core): render service

[samuelmasse]

This is a very simple interface meant to simplify the creation of payloads for builtin types.

const content = bp.render.text({ en: 'hello {{user.name}}', fr: 'salut {{user.name}}' })
// content.text : { en: 'hello {{user.name}}', fr: 'salut {{user.name}}' }
const translated = bp.render.translate(content, 'fr')
// translated.text : 'salut {{user.name}}'
const templated = bp.render.template(translated, { user: { name: 'bob' } })
// templated.text : 'salut bob'

You can also create a pipeline to avoid having to render, translate and template multiple payloads. You provide a language and a context and .translate and .template get automatically called

const render = bp.render.pipeline('fr', { user: { name: 'bob', age: 43, pin: 3030 } })
const text1 = render.text({ en: 'hello {{user.name}}', fr: 'salut {{user.name}}' })
// text1.text : salut bob
const text2 = render.text({ en: 'age : {{user.age}}', fr: 'âge : {{user.age}}' })
// text2.text : âge 43
const text3 = render.text('PIN : {{user.pin}}')
// text3.text : PIN 3030

It does not support the old way of storing translations with $en and $fr. I'm not sure what the state of that is, but preferably we would get rid of that and only use nested translations.

I'm also not sure how well this works alongside bp.cms. I made this to programmatically create payloads, so if someone decides to use the cms and this interface interchangeably, it probably won't work very well.

This also does not support custom content type renderers. I put a middleware in the cms for now. Basically any payload that doesn't have the new rendered property set to true gets rendered by its channel renderer. It's an hackish solution that's temporarily in place until content type renderers are removed/changed. I plan on reimplementing content type renderers as extensions to channels, and having our own builtin content types be processed with their default payload in all of our channels (so no renderers for them).

Typing indicators are also a problem. We'll need to adjust our channels so that all payloads can include typings indicators