Feature: #58033 - Enable label override of checkbox and radio buttons by TSconfig

See Issue #58033

Description

Use TSconfig to override labels of radio buttons and checkboxes used in FormEngine.

For single checkboxes the key default is used:

TCEFORM.pages.hidden.altLabels.default = individual label
TCEFORM.pages.hidden.altLabels.default = LLL:path/to/languagefile.xlf:individualLabel

For fields with multiple checkboxes, the value or the corresponding numeration (0,1,2,3) of the checkbox is used:

TCEFORM.pages.l18n_cfg.altLabels.0 = individual label for the first checkbox
TCEFORM.pages.l18n_cfg.altLabels.1 = individual label for the second checkbox

The same functionality works on radio buttons, where the “key” is the value of the radio button.

As seen in the example, hard-coded strings or references to language files are allowed.

Impact

The feature enables even more customization for FormEngine for any custom crafted backend instance.