ui: backup job: correctly align descriptions with fields in advanced options

ui: backup job: correctly align descriptions with fields in advanced options

Merges the column1/2/B into just single items so that the vertical
alignment is still correct even if a description wraps over multiple
lines.

Use the new pveTwoColumnContainer to achieve this without extra
boilerplate code and use a 1/3 of the width for the field and the 2/3
rest for the description.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
 [ TL: adapt to changes in prev. commit, reword message, fix eslint ]
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>