Allow platform admins to invite to particular roles

[techsmyth]

Description

As a platform admin I want to be easily able to invite a user to a particular role, for example as a beta tester or for the VC campaign

Acceptance criteria

• [ ] On the Platform Administration > Users page, add invitation section
• Pending invitations block
• "Invite" button which opens invite flow where a particular role can be selected: Roles supported: VC Campaign, Beta Tester

Additional Context

https://www.figma.com/design/jdQ4BlWUX7OOWZcqL2LOrU/Invite-to-platform-role?node-id=0-1&t=jzNrpJVPzWyV8cY5-1 This link might be replaced by: https://www.figma.com/design/aBqEUW5Whpqsybep4UQKF6/Platform-Administration?node-id=0-1&t=nqQ0xACekh0sBFwI-1

Areas that will be affected

To be added during the refinement