[book] add autoload section from code and fix sphinx warnings
* drop misleading faq entry since clear explanation can be found in internationalization chapter
* use autodata sphinx directive instead of raw text
* fill empty chapter with autodoc:
- devweb/httpcaching.rst
- devweb/resource.rst
- devweb/views/idownloadable.rst
- devweb/views/wdoc.rst
* use shebang in excerpt to denote shell code
* fix some bad indented docstrings in javascript files
Locate resources
----------------
.. automethod:: cubicweb.web.webconfig.WebConfiguration.locate_resource
.. automethod:: cubicweb.web.webconfig.WebConfiguration.locate_doc_file
.. automethod:: cubicweb.web.webconfig.WebConfiguration.locate_all_files
Static files handling
---------------------
.. automethod:: cubicweb.web.webconfig.WebConfiguration.static_directory
.. automethod:: cubicweb.web.webconfig.WebConfiguration.static_file_exists
.. automethod:: cubicweb.web.webconfig.WebConfiguration.static_file_open
.. automethod:: cubicweb.web.webconfig.WebConfiguration.static_file_add
.. automethod:: cubicweb.web.webconfig.WebConfiguration.static_file_del