Drop support for sysvinit scripts

As announced by a few releases now, finally drop support for
sysvinit scripts.
Keep rc-local generator for now, as it's really a distinct
feature even though from the same era.

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -133,7 +133,6 @@ body:
         - 'systemd-sysctl'
         - 'systemd-sysext'
         - 'systemd-sysusers'
-        - 'systemd-sysv-generator'
         - 'systemd-timedate'
         - 'systemd-timesync'
         - 'systemd-tmpfiles'

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -74,7 +74,6 @@ body:
         - 'systemd-sysctl'
         - 'systemd-sysext'
         - 'systemd-sysusers'
-        - 'systemd-sysv-generator'
         - 'systemd-timedate'
         - 'systemd-timesync'
         - 'systemd-tmpfiles'