Add per-field hide condition (new "Conditions to hide field" tab)

[UncleTomsCabi]

Currently, PluginFieldsContainerDisplayCondition only lets you hide the whole block when the main object matches a condition. This PR adds a separate mechanism to hide a single field of the block instead, without affecting the rest of the block. A new tab, "Conditions to hide field", appears on the container's edit page next to the existing "Conditions to hide block" tab. The two are independent: a block-level condition still hides everything, a field-level condition only hides the one field you pick. What's new

• New table glpi_plugin_fields_fielddisplayconditions and new class PluginFieldsFieldDisplayCondition (CommonDBChild of PluginFieldsContainer), mirroring PluginFieldsContainerDisplayCondition and delegating to it for the parts that don't depend on the storage table.
• New required "Field to hide" dropdown on the condition form.
• PluginFieldsField::prepareHtmlFields() now filters out fields whose condition matches the current item, before rendering — covers tab, dom/domtab and massive-action paths through a single integration point.
• New ajax/field_display_condition.php and front/fielddisplaycondition.form.php controllers, two new Twig templates.
• container.class.php::defineTabs() registers the new tab.