Change of attribute label in GUI

For users of the role termPM(allClients) it should be possible to change the label of an attribute. This change applies to the translate5 instance and thus to all termCollections of all clients.

A pencil icon should be added after the label, and once clicked - the label editing mode should be turned on. Label editing mode assumes that textfield should cover the label, but it should look same as label except cursor blinking, that would indicate that the label is currently editable. While in editing mode, the tooltip for that label-editor-textfield should be shown saying: 'Original label: <original label>'. Once changed on focusleave or ENTER-pressed:

1. new label should be saved in `terms_attribute_datatype`.`l10nCustom` json for that attribute
2. new label should be visually replicated to the same attributes on the other level-panels, if exist
3. new label should be visually replicated to the activeFilters-tags within filterPanel, and to the filterWindow's attributes, including labels for basic attributes (it's Process status only), 'Select an attribute' combobox option labels, and dynamic attributes, created by adding tags in that combobox
4. If user erase value from the label-editor-textfield  - custom value stored in `l10nCustom` - should be emptied, and system value should be applied back to GUI

In the change dialogue the original name should be displayed and the option to set/change a custom name for the current GUI language. A pencil icon behind the current name opens the editing dialogue.

To achieve this, the changed name must be added to the language-specific xliff in the client-specific folder of the corresponding translate5 installation (and changed there, if it is changed again later on).