Show active members in the Organization Admin

[faebebin]

Shows the active members, that have created a Job or a Delta for the Organization during the running stripe billing period in the admin.

The list of users in the detail view

(if no active members)

Dropped the active members count in the list_view - it would slow down too much:
It adds 4 Queries per organization. Without it is 6 Queries in total.

now:

before:

[duke-nyuki]

Task linked: QF-2604 Show a list of the active users in the Organization Admin

[faebebin]

There is sure potential to optimize the queries, currently is doing 45 queries for 2 active users, 41 queries for 1 active user. So it might get slow with many active users ... . Probably with some prefetch_related magic could be improved. Question is how much more effort want to put into optimizing this.

[faebebin]

Decided to simplify and only show a list of Users. Dropping the jobs and deltas count per user. Will therefore force push onto this PR. Will keep the current state on this branch https://github.com/opengisch/qfieldcloud/tree/QF-2604_org_active_users_job_deltas_count_detail_admin if we need the funcionality later

[suricactus]

@faebebin I assume it is not ready yet?

[suricactus]

Looks good, nice and simple. Please add the users on a new line makes things easier to read.