`\sphinxmaketitle` only exists as of v1.8.3, and `\renewcommand` would
crash when the command is not defined. Similarly `\newcommand` would
crash if the command already exists.
`\providecommand` acts as a shim: no-op if the command exists,
otherwise creates it so that it can be redefined.
- Update Enterprise & Partnership agreement (EN, FR)
- Update legal page index: hide outdated agreements, replace
with a link to an archive of the old PDFs.
- Add icons for missing files, to make index table layout more consistent
- Add `text-justify` on HTML versions of contracts, for consistency with
the PDF versions.
- Fix compatibility of PDF generation with recent sphinx versions
(\sphinxmaketitle instead of \maketitle)
- Re-add NL PDF building, still needs to be updated like all others
As of 1.6 and PR sphinx-doc/sphinx#3550, \ifsphinxpdfoutput is gone. It
was not really necessary in the first place, mostly a leftover from an
old copy of sphinx's \maketitle commands.
Also make the title slightly less huge ;-)
