feat: Add multiple items in a single input component

[AdityaHegde]

For user invite we need a single input that takes multiple items that can be deleted. This can also replace our inputs for user invite, slack users and slack channels in alerts/report forms.

[jkhwu]

Your screenshot looks good to me @AdityaHegde . Typically for error states on form items we also include a line below the box describing the error. Refer to https://www.figma.com/design/nqqazRo1ckU9ooC9ym9weI/Rill-Design-System?node-id=1155-275658&t=CI3PsT3M48ovZg4e-11

[jkhwu]

@AdityaHegde I know it's already been merged, but just tried the storybook component! Would it be possible to allow a comma , as a separating keystroke as well as enter? That's what I had discussed with @ericokuma when designing the UI for it (https://www.figma.com/design/Qt6EyotCBS3V6

O31jVhMQ7/RILL?node-id=13326-670655&t=CzdefMI7EkO6Q1IX-11)

[ericokuma]

Let's also add tab as another keystroke!

[AdityaHegde]

Sure i will incorporate these in the UI based user invitations PR.