refactor: prefer systemd sockets over socat

- Document preferred method for socket use depending on use case;
- Fix Github web-flow key;
- Standardize naming of services;
- Use sys-ssh in ansible formula;
- Start services conditionally with Qubes Service and evaluated by
  systemd ConditionPathExists= instead of installing on a per qube basis
  with rc.local scripts;
- Change Qusal services to "qusal-" prefix instead of "qubes-" prefix.

Fixes: https://github.com/ben-grande/qusal/issues/80
Fixes: https://github.com/ben-grande/qusal/issues/79

salt/sys-ssh/files/client/systemd/qusal-ssh-forwarder.socket

@@ -0,0 +1,17 @@
+# SPDX-FileCopyrightText: 2023 - 2024 Benjamin Grande M. S. <ben.grande.b@gmail.com
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+[Unit]
+Description=Forward SSH connection over Qrexec
+After=qubes-sysinit.service
+Before=qubes-qrexec-agent.service
+ConditionPathExists=/var/run/qubes-service/ssh-client
+
+[Socket]
+ListenStream=127.0.0.1:1840
+BindToDevice=lo
+Accept=true
+
+[Install]
+WantedBy=multi-user.target