Send invitation for subspace

[SimoneZaza]

Description

As a subspace admin, I want to be able to invite people to my Subspace

Acceptance criteria

• [ ] Show Invitation block on Subspace settings > Community (like on Space level, without the Magic URL button)
• [ ] Show Member guidelines block on Subspace settings > Community (like on Space level)
• [ ] When clicking on one of the invite buttons, check if user has the privilige to invite for (top level space). If not, show confirmation dialog with title: "Additional credentials needed" text: "Since Subspace members automatically become member of the Space as well, you need to have the credentials to invite people to the Space. Ask the Space admin to select this feature in the Space Settings."
• [ ] If the user has the privilige, act the same as in the space invite flow, thus opening a messaging dialog with either selection of Alkemio users or an email input field and then send the invitation

NB If AC 2 is difficult, we can of course only do the validation when the user tries to send the invitation, although this is not a nice UX. Someone may have put quite some effort in writing a nice invitation, so it would be frustrating to be blocked in the final step. If we do need to throw an error this way instead, please use the following text: "No rights: Ask the Space admin to change the Allowed Actions in the Space Settings"

Additional Context

All same as in Space:

Areas that will be affected

To be added during the refinement