Feat: Add Parking section and empty state

[AmaLuci]

During a call using the Phone island is possible to move the conversation to a Parking (on hold) using the specific button.

Calls in Parking can be resumed by any operator and it is therefore necessary to add a section where operators can view calls on hold and pick them up.

We'll add the Parking section in the right sidebar of NethLink.
The section will remain empty (an empty state is expected) and will be populated with a list of calls with the related information when present.

Behavior (same as NethVoice CTI):
When an operators clicks on "Parking" during a call, the call goes to "Parking" section on hold.
Every operator can pick up the call from the section, which activate the Phone island and resume the call.
Every operator will see a "red dot" as notification that the parking has at least a call on hold.
System notification isn't necessary.

Notification:
When a call is added on Parking a pulsing "red dot" appears pulsing for few seconds (same behavior than on calls for a missing call, on about for updates). See Ping animation.

Empty state:
If a section is empty, as Parking without calls or Speed dials without contacts, we display an empty state as designed.

Mockups ready on Figma

Images as reference