ino-snackbar: add property for custom container id

[janivo]

Description

Currently, the ino-snackbar component is mounted to the document.body by default, which may not always be desirable, especially in scenarios where the application layout involves multiple containers. To address this limitation and provide more flexibility, a new property needs to be added to the ino-snackbar component to allow developers to specify a custom container ID where the snackbar should be mounted. This enhancement will enable use cases such as fullscreen modes where the snackbar should be appended to a specific container within the DOM.

Acceptance Criteria

• A new property, such as customContainerId, is added to the ino-snackbar component.
• The ino-snackbar component is updated to append to the specified custom container ID when provided.
• Error handling is implemented to throw an error if the specified custom container ID is not found within the DOM.
• The component's documentation is updated to include information about the new property and its usage.

Test Cases

1. Custom Container ID Provided

   • Provide a custom container ID to the ino-snackbar component.
   • Verify that the snackbar is correctly appended to the specified custom container ID when rendered.

2. Error Handling

   • Attempt to provide a non-existent custom container ID to the ino-snackbar component.
   • Confirm that an error is thrown, indicating that the specified custom container ID is not found.

Additional Information

We've implemented the same feature for the ino-tooltip and ino-popover. Have a look!

[janivo]

postponed until #1319 is done