Deprecated global function "now" because it's equivalent to Varien_Date::now()

[Sdfendor]

Description (*)

There are currently two now methods that are doing the exact same thing, returning the formatted version of the current timestamp either with or without the time part (Besides those there is a third one within Zend that does a similar thing but is not part of this PR).

global now (app/code/core/Mage/Core/functions.php):

/**
 * Simple sql format date
 *
 * @param bool $dayOnly
 * @return string
 */
function now($dayOnly = false)
{
    return date($dayOnly ? 'Y-m-d' : 'Y-m-d H:i:s');
}

Varien_Date (lib/Varien/Date.php):

/**
 * Retrieve current date in internal format
 *
 * @param boolean $withoutTime day only flag
 * @return string
 */
public static function now($withoutTime = false)
{
    $format = $withoutTime ? self::DATE_PHP_FORMAT : self::DATETIME_PHP_FORMAT;
    return date($format);
}

the used constants:

const DATETIME_PHP_FORMAT       = 'Y-m-d H:i:s';
const DATE_PHP_FORMAT           = 'Y-m-d';

It's clear to see that both functions are equivalent. I propose:

1. To deprecate global function now
2. To reference the replacement Varien_Date::now()
3. To use the replacement call instead of the redundant code

In subsequent PRs the following changes can be implemented:

1. For v19 occurrences of deprecated global function shall be replaced one-to-one
2. For v20 deprecated global function shall be removed

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All automated tests passed successfully (all builds are green)

[github-actions]

Unit Test Results

0 files   - 1  0 suites   - 1   0s ⏱️ ±0s
0 tests ±0  0 ✔️ ±0  0 💤 ±0  0 ❌ ±0 
0 runs   - 7  0 ✔️  - 5  0 💤  - 2  0 ❌ ±0 

Results for commit e3d66a5. ± Comparison against base commit 438639f.