Add public datasets under "Hub"

[GspikeHalo]

Purpose:

Added a new interface for public datasets, allowing non-logged-in users to view datasets shared by others. The behavior of public datasets aligns with that of public workflows, ensuring consistent access and interaction with public resources.

Changes:

1. Added "Hub Dataset" to the left sidebar. Clicking on it will display public datasets.
2. Updated the list item behavior: When a user clicks a list item of type "dataset," different navigation actions are taken depending on the situation:
   • If the user is not logged in, they will always be redirected to the Hub Dataset page. This page disables the download
     functionality and does not display the publish switch.
   • If the user is logged in but lacks direct access permissions (e.g., read or write), they will still be redirected to the Hub Dataset page.
   • If the user is logged in and has read or write permissions, they will be redirected to the User Dataset page, which is the original dataset page we had.

Demos:

Before:
Left sidebar:

After:
Left sidebar:

Public Dataset Interface Before Login:

Public Dataset Interface After Login:

Non-logged-in user clicking any dataset:

Logged-in user without direct permissions clicking any dataset:

Logged-in user with direct permissions clicking any dataset:

[chenlica]

Please modify the description to make it clear that the behaviors of Public Datasets are similar to those of Public Workflows.

[aglinxinyuan]

LGTM!