Complete the UI for Link Shortner Add Link Screen

[tarashagarwal]

path: /link/add

We need to bring back the existing Link Shortener Elements to the the migrated app.

Previous App:

The theme of the new app should meet that of the Management UI Theme, so please avoid adding new CSS if not essential.

Concept Screen:

Thanks @EthM370 for pointing out:
Refer the following Regex to validate the input slug: #### ^(https?://)?[a-zA-Z0-9-._/]*$ ####

if the verification of the above Regex fails. Red outline the box and display message "Invalid input: Only alphanumeric characters, '-', '_', '/', and '.' are allowed". - all these features should be included in the manticore package, please explore... or check how it is already being done in the Management UI, we can copy that.

Hard-code any data that is required for now... do not aim to call APIs untill they are developed.

Features to be added:
Instead of multiple check boxes, we will use multi-select drop-down: https://mantine.dev/core/multi-select/
Need to add a generate URL Button as in the original app - generates

Reach Out for Any Questions!!