[web] Create link view modal

Summary:
Display the modal after button click. The modal contains all the necessary info but doesn't handle copying yet.

Depends on D8237

Test Plan: Open the modal and check if it is displayed correctly.

Reviewers: bartek, kamil, inka

Reviewed By: inka

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D8238