Add Pantalaimon support

This is actually authored by Julian Foad here
(https://lab.trax.im/matrix/matrix-docker-ansible-deploy), but was in
need of a rebase and various adjustments caused by huge playbook
refactoring that landed in the past months.

This rework is completely untested.

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/266

roles/custom/matrix-pantalaimon/templates/pantalaimon.conf.j2

@@ -0,0 +1,10 @@
+[Default]
+LogLevel = {{ matrix_pantalaimon_log_level }}
+
+[homeserver]
+Homeserver = {{ matrix_pantalaimon_homeserver_url }}
+ListenAddress = 0.0.0.0
+ListenPort = 8009
+SSL = False
+UseKeyring = False
+IgnoreVerification = True