- Don't setup username+password from config file during fresh install.
- If `LISTMONK_ADMIN_USER` and `LISTMONK_ADMIN_PASSWORD` env vars are
set during `--install`, use them.
- Otherwise, render new username+password creation UI on `/admin/login`.
- Add Cypress tests.
This commit splits roles into two, user roles and list roles, both of which
are attached separately to a user.
List roles are collection of lists each with read|write permissions, while
user roles now have all permissions except for per-list ones.
This allows for easier management of roles, eliminating the need to clone and
create new roles just to adjust specific list permissions.
