Initial semaphore 2.19.8 package with service, container and postgresql subpackages

Semaphore UI packaged from the upstream community (MIT) release
binaries, following the gitea packaging pattern: native systemd service
and Podman quadlet variants (mutually exclusive), with an optional
PostgreSQL backend via quadlet drop-ins. SQLite is the default
database; session/encryption secrets are generated into
/etc/semaphore/env on first install.

semaphore.service

@@ -0,0 +1,18 @@
+[Unit]
+Description=Semaphore UI - modern UI for Ansible, Terraform and OpenTofu
+Documentation=https://docs.semaphoreui.com/
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+User=semaphore
+Group=semaphore
+WorkingDirectory=/var/lib/semaphore
+EnvironmentFile=/etc/semaphore/env
+ExecStart=/usr/libexec/semaphore server --config /etc/semaphore/config.json
+ExecReload=/bin/kill -HUP $MAINPID
+Restart=always
+RestartSec=3
+
+[Install]
+WantedBy=multi-user.target