See inactive accounts in admin interface

Changes proposed in this pull request:

In the user overview of admins, you can choose to only see admins
In the user overview of admins, you can filter on accounts that have a login method that hasn't been used in n days (or that never logged in since we kept track of the last login date)
Add last login dates to data generation

How to test:

docker compose down --volumes && docker compose build --parallel && docker compose up --scale data-generation=1
Log in as admin, go to http://localhost/admin/rsd-users
Assign some more admins, toggle the extra switch, you should only see admins
Enter a positive number in the Last login input, you should only see accounts that have a login method where the last login date is either missing or older than the amount of days you entered
Combine multiple filters together, is the output correct?

PR Checklist:

research-software-directory / RSD-as-a-service