[FIX] account: default partner format

When creating a new account.move.line, the computation of the default values should accept both `id` and `(id, name)` format.
The key partner_id may be containing a tuple so browsing should only be done on the first element of the tuple.
Fixes #3386
[IMP] doc: link logo to current doc's root, not to odoo.com
[IMP] doc: add link to company website in footer, fix release version
[IMP] doc: link directly to edition mode in docfiles
[FIX] updates the graph view documentation

It was wrong.