Use suggested-action class

GTK has two classes for buttons: .suggested-action and .destructive-action
I think we should try to use them when it is appropriated.

assigned to @ced

added tryton type::behavior + 1 deleted label

added 1 deleted label and removed 1 deleted label

review60281002 updated at https://codereview.tryton.org/60281002/#ps1

New changeset 48b74e2b64c8 by Cédric Krier in branch 'default':
Add style class to buttons of login and wizard
https://hg.tryton.org/tryton/rev/48b74e2b64c8

added 1 deleted label and removed 1 deleted label

closed

New changeset 1718e5416dc9 by Cédric Krier in branch 'default':
Add style class to buttons of login and wizard
https://hg.tryton.org/tryton-env/rev/1718e5416dc9