[NavidSassan]

Adds proxysql to tools/follow-upstream.yml and merges the packaged proxysql.cnf of 3.0.11 into the template (Based on 3.0.8 before; 2.7.4 and 3.0.8 ship the identical file).

• RPM only: the role supports the RHEL family only, and upstream uses a flat APT repository the tool does not support.
• One shared template for 2.7 and 3.0: rendered with the role defaults and a full variable set, ProxySQL 2.7.4 and 3.0.11 start in Rocky 9 containers with the old and with the merged template and load all values; a broken config is caught (negative control). 2.7 accepts the new (empty) 3.0 sections.
• Install scripts never touch /etc/proxysql.cnf; the package ships it as root:proxysql 0640, as the role does.

tools/follow-upstream --check proxysql returns 0. Without #501, --check does not notice a later series (3.1) for this template.