[i18n] [oc-panel] fields.php : Fix variable strings

added 6 sprintf('... %s ...', $var)
Fix Breadcrumbs title
Added i18n string
Added i18n string
Added i18n string
Added data-placeholder for Categories select list
Added 2 help-blocks explanations
Added 3 help-blocks explanations
Added data-placeholder for Categories select list
Added i18n string
Added i18n string
Merge pull request #850 from emanwebdev/i18n

[i18n] Fixes + new help blocks + new placeholders for Chosen