[gdal-dev] [Docs] Propose localization of gdal documentation

[ｍｉｕｒａ＠ｌｉｎｕｘ]

Hi

I'd like to propose to move gdal doc to be i18n-ed.

Now documentations are compiled with sphinx, and sphinx has a good i18n/l10n facility, and it is very easy..
If you are welcome for the move, I'd like to propose some updates for gdal github project.

* How to i18n-ed sphinx documentation.

1. add `locale_dirs = ['locale/']` to `doc/source/conf.py`
2. `$ pip install sphinx-intl`
3. run `$ make gettext` and `$ sphinx-intl update -l ja -l de`
4. Translate generated PO files under `doc/source/locale/<lang>/LC_MESSAGES/`
5. `$ make -Dlanguage=ja html`

When we are ready to provide i18n documentation with translated PO files,
we can produce localized html using sphinx on azure-pipelines.

I'd ike to contribute a Japanese translation of documentations.
So I have a private project to do that using OmegaT CAT tool.

https://github.com/miurahr/gdal_docs_ja

--
Hiroshi