Ensure reliable /etc/hosts handling for EasyEngine in containerized environments

### Description:

This change ensures that EasyEngine can reliably handle `/etc/hosts` entries when deployed in Docker or containerized environments, without affecting functionality on host systems.

### Context:

When EasyEngine is run inside a container, its attempt to update the host system's `/etc/hosts` file via a mounted volume may silently fail due to permission or compatibility issues in the `Filesystem()->dumpFile()` method.

-> [Deploy Easyengine-Docker](https://easyengine.pages.dev/notes/easyengine-docker/)

```php
/**
* Removes entry of the site from /etc/hosts
*
* @param string $site_url site name.
*
*/
function remove_etc_hosts_entry( $site_url ) {
$fs = new Filesystem();

$hosts_file = file_get_contents( '/etc/hosts' );

$site_url_escaped = preg_replace( '/\./', '\.', $site_url );
$hosts_file_new = preg_replace( "/127\.0\.0\.1\s+$site_url_escaped\n/", '', $hosts_file );

$fs->dumpFile( '/etc/hosts', $hosts_file_new );
}
```

### Objective:

**Not to change existing behavior**, but to **ensure consistent and reliable operation** of the `remove_etc_hosts_entry` function across environments, especially in container deployments.

### Modifications:

Refactored `remove_etc_hosts_entry` in `src/helper/site-utils.php` to use PHP's native file I/O operations with added safety and compatibility:

* Replaced `Filesystem()->dumpFile()` with `file_put_contents()` and `file_get_contents()`.
* Added `LOCK_EX` to ensure atomic writes.
* Used `stream_context_create` with `'file' => ['privileged' => true]` to improve write permissions handling in volume-mounted `/etc/hosts`.
* Implemented `preg_quote()` to safely match hostnames.
* Included explicit error handling for file read/write failures.

### Benefits:

* **Container Compatibility**: Improves EasyEngine’s robustness when run in Docker or similar environments.
* **Backward-Safe**: Function continues to work without modification on traditional (host-level) deployments.
* **Resilience**: Adds clear error messages in case of failure, reducing silent breakages.

### Testing:

* Verified successful read/write operations to `/etc/hosts` in:

* Docker container with volume-mounted `/etc/hosts`
* Host-level execution without container

### Updated Function:

```php
/**
* Removes entry of the site from /etc/hosts
*
* @param string $site_url site name.
*
*/
function remove_etc_hosts_entry($site_url) {
$hosts_file = @file_get_contents('/etc/hosts');
if ($hosts_file === false) {
throw new Exception("Failed to read /etc/hosts");
}

$site_url_escaped = preg_quote($site_url, '/');
$hosts_file_new = preg_replace("/127\.0\.0\.1\s+$site_url_escaped\n/", '', $hosts_file);

$context = stream_context_create([
'file' => ['privileged' => true]
]);

$result = file_put_contents('/etc/hosts', $hosts_file_new, LOCK_EX, $context);
if ($result === false) {
throw new Exception("Failed to update /etc/hosts");
}
}
```