Updated: The file manifest carries the checksums of the move to top and bottom files

Updated: German for the class editor's move to top and move to bottom buttons

Added: Move a class attribute to the top or the bottom, in place, from the class editor

Beside the up and down arrows each attribute has a "move to the top" and
a "move to the bottom" button. They work like the arrows: the row moves
at once, the positions and priorities are renumbered, the server stores
it, and a move the server does not store is put back with a message.
With JavaScript off they post the form like the arrows do.

- eZContentClassAttribute::moveToEdge() puts the attribute first or
  last; the others keep their order and are numbered 1..n.
- class/edit handles MoveTop and MoveBottom, in place and as a form post.
- The in-place move answers carry X-Class-Attribute-Moved: 1, and the page
  accepts a move only with it: a server that does not handle the action
  answers an ordinary page (200), which was taken as a stored move.
- After every move the priority fields follow the rows, so Apply and OK
  store the order shown.

Verified in a browser on Apache and on Velocity: to the top and to the
bottom without a reload, each kept after a reload; up and down as
before; a refused move put back; and with JavaScript off, a move to the
bottom by form post.

Updated: The file manifest carries the checksums of the class attribute move fixes

Fixed: A class attribute moves one place even when attributes share a placement

eZContentClassAttribute::move() swaps the attribute with the next one
by placement, with nothing to tell attributes of the same placement
apart. With duplicate or missing placements (imported or old classes)
the swap changed nothing, or swapped two other attributes, depending on
the database's order. The class version's placements are now renumbered
1..n (by placement, then id) first when they are not that already, and
the move requests load the attribute's id for it.

Verified with a class whose attributes were given tied and gapped
placements: the attribute moved exactly one place and the placements
were 1..n afterwards.

Fixed: Moving a class attribute up or down happens in place again, and the page shows the order the server stored

The class edit page's script called jQuery's .size(), which jQuery 3
removed (the admin loads 3.7.1). The call threw on the script's first
line, before the move buttons were set up, so every arrow posted the
whole form and reloaded the page; with an older jQuery, or where jQuery
Migrate was loaded, it worked, which is why it worked only sometimes.

- .length instead of .size() here, in the translation step of content
  edit (edit_languages.tpl) and in the relations script.
- After a move the position numbers and the row colours follow the rows;
  they kept their old values before.
- A move the server does not confirm (refused, failed, no answer) is put
  back and the page says so; before, the page and the stored order
  silently went apart.
- The request sends the X-CSRF-Token header as well as the form token.

Verified in a browser: a move down and back up without a reload, each
answered 200, the order unchanged by a reload, and a refused move put
back with a message.

Updated: The file manifest carries the checksum of the extensions view