…0793)

Introduces new `{% tabs "save-key" %}` and `{% tab "name" %}`
11ty/Liquid paired shortcodes to add tabs to the site and switches the
various tab methods across the site (`codesample` and raw HTML) to use
them.

The `save-key` parameter is optional and allows syncing of tabs across
the site to the same tab. For example, the `darwin-language` key is used
to switch all tabs with the same key to either `Swift` or `Objective-C`.
The `name` parameter tab is not optional. Both `save-key` and `name`
must be in quotes or refer to a Liquid/11ty variable that is a string.
The `{% endtab %}` and `{% endtabs %}` closing shortcodes are required
to close a tab and a tab menu respectively.

**Example:**

````liquid
{% tabs "darwin-language" %}
{% tab "Swift" %}

Some words about the following Swift snippet...

```swift
let flutterViewController = FlutterViewController(
project: nil, initialRoute: "/onboarding", nibName: nil, bundle: nil)
```

{% endtab %}
{% tab "Objective-C" %}

Some words about the following Objective-C snippet...

```objc
FlutterViewController* flutterViewController =
      [[FlutterViewController alloc] initWithProject:nil
                                        initialRoute:@"/onboarding"
                                             nibName:nil
                                              bundle:nil];
```

{% endtab %}
{% endtabs %}
````

Resolves #8926
Contributes to #8889
Contributes to #8030