Reorganized locale directories and added Transifex for managing the translation process

[tobiasmcnulty]

We had some old PO files for English and French in the repo, but they were sorely out of date and it's high time we switched to something more modern for managing the translation process. I also discovered recently that we were not running compilemessages during deploy, so the few translations we did have weren't even showing up. That has now been fixed, so let's add and update translations! 😄

This PR:

• Adds a new locale directories in the dashboard app and at the project level (in addition to docs/locale/ that we already had). This gives us one locale/ directory for each website domain and allows us to map the corresponding PO files to different places in Transifex.
• Adds transifex-client to the dev requirements, a new .tx/config to do the locale -> resource mapping, and some process docs for managing translations.
• Updates the one translation that we already had (French) with the updated translation files from Transifex
• Includes a script to update translations in the future, based on: https://github.com/django/django-docs-translations/blob/stable/2.1.x/manage_translations.py#L54-L72

Much credit due to @m-aciek and @claudep for helping to brainstorm and arrive at this solution!

One question: I copied the list of supported languages from the script in django-docs-translations, but I'm not sure if we need to keep those in sync or not. I guess we should at least aim to support at least those languages but potentially more, for djangoproject.com...(?)

Finally, a few things that can or will happen separately from this PR:

• I opted not to include translations of other languages in this stage to help keep the size of the PR down. But if/when this is approved and merged, we should pull and commit all the new translations shortly after.
• I also opted not to add any new strings (yet). There is a separate issue for localizing the fundraising app which could be a good first step after this (Localize the fundraising app #377).
• We'll need to decide how we want language switching to work for sites other than docs. See disable LocaleMiddleware for docs.djangoproject.com #862.

[m-aciek]

According to what I've written in email, it occures that I didn't published my review (can't do it in mobile view, had to switch to desktop). Sorry for confusion.

Publishing now :)

[tobiasmcnulty]

Thanks for all your help and feedback @claudep and @m-aciek.

I think this should be ready for another review.

[tobiasmcnulty]

And your translation at work: https://www.dropbox.com/s/6vjkpxhmbde61dk/Screenshot%202019-02-18%2021.57.32.png?dl=0 😄

[tobiasmcnulty]

@m-aciek Would you like to give this another review?

And/or @timgraham would you like to review before merging?

Thanks!

[m-aciek]

Docs' PO files have sth more similar to:

Suggested change

	# This file is distributed under the same license as the PACKAGE package.
	# Copyright (C) Django Software Foundation and contributors
	# This file is distributed under the same license as the djangoproject.com source files.

here.

Should it be set in Transifex to work automatically?

If it is configurable, I'd also suggest to drop the lines SOME DESCRIPTIVE TITLE. and FIRST AUTHOR <EMAIL@ADDRESS>, YEAR..

[claudep]

I guess this is mostly controlled by Transifex, I don't know yet if that can be customized or not. We could also remove French files from this commit, and add them with other languages in a separate PR.

[tobiasmcnulty]

If it can be changed in Transifex that would be great. Do you know if that's possible and where to do it if so? I'm not finding anything in the UI or their documentation...

Or for the Django docs is it handled through post-processing (like removal of the file locations)?

[tobiasmcnulty]

Silly me. I just needed to change this in the source file, and then push/pull to update in the translations.

[tobiasmcnulty]

This should be ready for another review.

[tobiasmcnulty]

This has been deployed!