Allow configuration of the email address to send invitations from

Is your feature request related to a problem? Please describe.

When creating an event and inviting people, an invitation is sent to them. The invitation is always sent from nextcloud@domain.tld and the logo of the Nextcloud instance is included as well.

I may not want to tell them that I am using Nextcloud, nor any other service, so:

• I would rather not share with them the details of the Nextcloud instance I am using
• I would rather not share with them the instance's configured email address
• I would rather not include Nextcloud or the instance's configured logo

Describe the solution you'd like

• Be able to configure an email address to send those invitations from, ideally, this should be configurable per-calendar (i.e.: I may have a personal and a professional calendar and I would like to send invitations from different email addresses in those cases)
• Be able to remove the Nextcloud/instance logo from the invitation, or be able to replace that logo with my user avatar, or be able to define my own invitation template

Additional context

See also: https://github.com/nextcloud/calendar/issues/2591

No files or tests are named in the issue. Start by reviewing the related issue #2591 and tracing the calendar invitation flow; done means invitations can use a configurable sender and provide the requested control over branding or templates, including the per-calendar case.