Big area mark as read

Fix MySQL error, which appeared in MySQL 5.7:

ERROR 1055 (42000): Expression #1 of SELECT list is not in GROUP BY
clause and contains nonaggregated column 'freshrss.c.id' which is not
functionally dependent on columns in GROUP BY clause; this is
incompatible with sql_mode=only_full_group_by

There was an erroneous '; at the end of the commitNewEntries DELETE query, resulting in an exception during actualization with this output:

```
FreshRSS starting feeds actualization at 2021-01-11T14:06:09+00:00
FreshRSS actualize candrews...
PHP Fatal error:  Uncaught PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ''' at line 1 in /var/www/localhost/htdocs/FreshRSS/lib/Minz/Pdo.php:45
Stack trace:
#0 /var/www/localhost/htdocs/FreshRSS/lib/Minz/Pdo.php(45): PDO->exec()
#1 /var/www/localhost/htdocs/FreshRSS/app/Models/EntryDAO.php(167): Minz_Pdo->exec()
#2 /var/www/localhost/htdocs/FreshRSS/app/Controllers/feedController.php(505): FreshRSS_EntryDAO->commitNewEntries()
#3 /var/www/localhost/htdocs/FreshRSS/app/Controllers/feedController.php(548): FreshRSS_feed_Controller::actualizeFeed()
#4 /var/www/localhost/htdocs/FreshRSS/lib/Minz/Dispatcher.php(119): FreshRSS_feed_Controller->actualizeAction()
#5 /var/www/localhost/htdocs/FreshRSS/lib/Minz/Dispatcher.php(47): Minz_Dispatcher->launchAction()
#6 /var/www/localhost/htdocs/FreshRSS/lib/Minz/FrontController.php(81): Minz_Dispatcher->run()
#7 /var/www/localhost/htdocs/FreshRSS/app/actualize_script.php(75): Minz_FrontController->run()
#8 {main}
  thrown in /var/www/localhost/htdocs/FreshRSS/lib/Minz/Pdo.php on line 45
Results:
```

#fix FreshRSS#3401 (crash with PHP 8+)

`ceil()` crashes in PHP8+ in case of invalid input such as empty string.
`intval()` fixes the problem with almost identical behaviour than `ceil()` in PHP7- (except for floating point values)

#fix FreshRSS#3401 (crash with PHP 8+)

Example with feed http://podcast.hr2.de/derTag/podcast.xml

```xml
<enclosure url="https://mp3podcasthr-a.akamaihd.net:443/mp3/podcast/derTag/derTag_20210129_87093232.mp3"
length="" type="audio/mpeg"/>
```

`isset("")` passes and then `ceil("")` crashes due to wrong type in PHP8+:

```
Uncaught TypeError: ceil(): Argument #1 ($num) must be of type
int|float, string given in ./SimplePie/SimplePie/Item.php:2871
```

Upstream patch simplepie/simplepie#670

#fix FreshRSS#3546
When `loadHTML()` is given a null or empty string.

```
PHP Fatal error:  Uncaught ValueError: DOMDocument::loadHTML(): Argument #1 ($source) must not be empty in /var/www/freshrss/lib/SimplePie/SimplePie/Locator.php:83
```

#fix FreshRSS#3546
When `loadHTML()` is given a null or empty string.

```
PHP Fatal error:  Uncaught ValueError: DOMDocument::loadHTML(): Argument #1 ($source) must not be empty in /var/www/freshrss/lib/SimplePie/SimplePie/Locator.php:83
```

Fix regressions from FreshRSS#4561

Example:

```
PHP Fatal error:  Uncaught TypeError: Argument 1 passed to checkToken() must be an instance of FreshRSS_UserConfiguration, instance of Minz_Configuration given, called in /var/www/FreshRSS/p/api/greader.php on line 1091 and defined in /var/www/FreshRSS/p/api/greader.php:223
Stack trace:
#0 /var/www/FreshRSS/p/api/greader.php(1091): checkToken()
#1 {main}
  thrown in /var/www/FreshRSS/p/api/greader.php on line 223
```

Improvement of FreshRSS#4110

Fix regressions from FreshRSS#4561

Example:

```
PHP Fatal error:  Uncaught TypeError: Argument 1 passed to checkToken() must be an instance of FreshRSS_UserConfiguration, instance of Minz_Configuration given, called in /var/www/FreshRSS/p/api/greader.php on line 1091 and defined in /var/www/FreshRSS/p/api/greader.php:223
Stack trace:
#0 /var/www/FreshRSS/p/api/greader.php(1091): checkToken()
#1 {main}
  thrown in /var/www/FreshRSS/p/api/greader.php on line 223
```

Improvement of FreshRSS#4110

Not really used, and causing bug in FreshRSS#5942

```
Fatal error: Uncaught Error: Typed property FreshRSS_View::$default_category must not be accessed before initialization in /var/www/FreshRSS/app/views/helpers/category/update.phtml:218 Stack trace: #0 /var/www/FreshRSS/lib/Minz/View.php(93): include() #1 /var/www/FreshRSS/lib/Minz/View.php(143): Minz_View->includeFile() #2 /var/www/FreshRSS/app/views/category/update.phtml(9): Minz_View->renderHelper() #3 /var/www/FreshRSS/lib/Minz/View.php(93): include('...') #4 /var/www/FreshRSS/lib/Minz/View.php(115): Minz_View->includeFile() #5 /var/www/FreshRSS/lib/Minz/View.php(75): Minz_View->render() #6 /var/www/FreshRSS/lib/Minz/Dispatcher.php(59): Minz_View->build() #7 /var/www/FreshRSS/lib/Minz/FrontController.php(61): Minz_Dispatcher->run() #8 /var/www/FreshRSS/p/i/index.php(59): Minz_FrontController->run() #9 {main} thrown in /var/www/FreshRSS/app/views/helpers/category/update.phtml on line 218
```

Not really used, and causing bug in FreshRSS#5942

```
Fatal error: Uncaught Error: Typed property FreshRSS_View::$default_category must not be accessed before initialization in /var/www/FreshRSS/app/views/helpers/category/update.phtml:218 Stack trace: #0 /var/www/FreshRSS/lib/Minz/View.php(93): include() #1 /var/www/FreshRSS/lib/Minz/View.php(143): Minz_View->includeFile() #2 /var/www/FreshRSS/app/views/category/update.phtml(9): Minz_View->renderHelper() #3 /var/www/FreshRSS/lib/Minz/View.php(93): include('...') #4 /var/www/FreshRSS/lib/Minz/View.php(115): Minz_View->includeFile() #5 /var/www/FreshRSS/lib/Minz/View.php(75): Minz_View->render() #6 /var/www/FreshRSS/lib/Minz/Dispatcher.php(59): Minz_View->build() #7 /var/www/FreshRSS/lib/Minz/FrontController.php(61): Minz_Dispatcher->run() #8 /var/www/FreshRSS/p/i/index.php(59): Minz_FrontController->run() #9 {main} thrown in /var/www/FreshRSS/app/views/helpers/category/update.phtml on line 218
```