### Features

#### Inline "insert" Markdown

_Usage example_:

```yaml
++text++
```

is converted to:

```html
<ins>text</ins>
```

### Fixes

- Footnotes are now removed in excerpt
- Checks if config file is exists / is defined
- Variable `$layout` might not be defined
- `str_replace` PHP function is fixed for PHP 8
- `bindtextdomain` is set only if the `locale` (l10n) exists
- Asset images optimization fixed
- Extension `.ser` added to cache files
- Assets resize process fixed
- Assets are optimized on `save()`

### Misc

- Dependencies updated
- Docs charts updated
- `declare(strict_types=1)` added to all library files
- Code cleaned