Add back render callback pattern for v10

[rosskevin]

Is your feature request related to a problem? Please describe.
/from #703 (comment)

Currently the render callback from v9 was dropped but a the hoc is retained. That's too hard of a break in my opinion for class-based users. I for one am exclusively using it over the hoc, and we have many classes to convert before we can use hooks.

Describe the solution you'd like
I suggest strongly that a render callback needs to be included in v10.

Describe alternatives you've considered
If leaving this as-is I would have two choices:

• convert my entire class code to functions and hooks (not incremental)
• convert my entire function code to hooks AND convert all NamespaceConsumer usage to hocs or functions and hooks.

[jamuhl]

TranslationRenderProp ? or do you have an idea for a good naming?

[rosskevin]

I would just use Translation to provide the pattern - consistent in naming to useTranslation and withTranslation.

[jamuhl]

okey

[jamuhl]

Translation render prop landed in react-i18next@10.0.0-alpha.2