[Feat]: ability to create an invite link to share directly with a user

[andrewm4894]

Problem

sometimes invite emails can be slow or get lost.

Description

it would be good if instead i could copy the invite link for a user and just share it with them however i want - eg on slack etc.

Importance

nice to have

Value proposition

1. quicker and easier to add users to spaces

Proposed implementation

similar to how this works currently in posthog - when inviting a new user it sends them the email but you can also just copy the link for that user and share direct with them.