Feature: #108431 - Add TCA datetime format=datetimesec option

Description

The TCA configuration config option type=datetime can now specify the format=datetimesec format to offer a date/time picker for entering a date (day, month, year) with a specific time (hour, minute, second).

Previously, only a datepicker for hour and minute was available, even though the utilized component (Flatpickr) supports entering seconds.

This format can either be specified for dbType=datetime (native SQL datetime columns based on a timestamp that always includes seconds) or for the integer-based storage without a dbType option (UNIX timestamp).

Example TCA configuration:

EXT:my_extension/Configuration/TCA/tx_domain_model_myelement.php

<?php

return [
    // ...
    'columns' => [
        'meteor_impact' => [
            'label' => 'Time of estimated impact',
            'config' => [
                'type' => 'datetime',
                'format' => 'datetimesec',
                'dbType' => 'datetime', // can also be omitted for integer-based storage
                'nullable' => true, // can also be false
            ],
        ],
    ],
    // ...
];

Hint

The format datetimesec is only allowed for:

empty ['config']['dbType'] (defaults to integer-based storage type)
['config']['dbType'] = 'datetime' (native date and time storage type)

Other types (date, time, timesec) do not support both components and would yield unconsistent data.

Impact

Editors and integrators can now specify dates including seconds in database record fields, if the fields are configured with the new TCA config format datetimesec.

This can be set for any TCA field that already internally receives a UNIX timestamp value.

-- For the editor who has everything, but seconds.