Shorten path for XDG_CONFIG_HOME and clean dir

In Linux socket paths are limited to 108 char length.
/var/tmp/vm/$UID/.config will be too long in some cases.
So we use /var/tmp/vm/$UID

/var/tmp/vm must be
- cleaned on startup
- created with sticky-bit (used by different users)

roles/lmn_vm/files/pam-umount.sh

@@ -13,12 +13,12 @@ slp=false
 shutdownVMs(){
     local VM
     for VM in $(sudo -u $usr XDG_RUNTIME_DIR="/run/user/$uid" \
-		     XDG_CONFIG_HOME="/var/tmp/vm/$uid/.config" \
+		     XDG_CONFIG_HOME="/var/tmp/vm/$uid" \
 		     XDG_CACHE_HOME="/var/cache/user/$uid/" \
 		     virsh list --state-running | \
 		    sed -nE "s/.*\s+(\S+)\s+running/\1/p") ; do
 	sudo -u $usr XDG_RUNTIME_DIR="/run/user/$uid" \
-	     XDG_CONFIG_HOME="/var/tmp/vm/$uid/.config" \
+	     XDG_CONFIG_HOME="/var/tmp/vm/$uid" \
 	     XDG_CACHE_HOME="/var/cache/user/$uid/" \
 	     virsh destroy "$VM" 2>&1 | systemd-cat || true
 	slp=true

roles/lmn_vm/files/vm-netboot

@@ -5,7 +5,7 @@
 set -eu
 
 ## Imporant for all virsh libvirt calls:
-export XDG_CONFIG_HOME="/var/tmp/vm/${UID}/.config"
+export XDG_CONFIG_HOME="/var/tmp/vm/${UID}"
 
 menu=(standard "CLI Standard Debian GNU/Linux NFS"
       standard-ram "CLI Standard Debian GNU/Linux RAM"

roles/lmn_vm/files/vm-run

@@ -295,7 +295,7 @@ if [[ "${PERSISTENT}" == 1 ]] && [[ ! -f "${VM_DIR_PERSISTENT}/${VM_NAME}.qcow2"
 fi
 
 # because virsh has problems with long pathnames, using diffent configdir
-export XDG_CONFIG_HOME="/var/tmp/vm/${UID}/.config"
+export XDG_CONFIG_HOME="/var/tmp/vm/${UID}"
 
 if  ! virsh --connect="${QEMU}" list | grep "${VM_NAME}-clone"; then
     echo "VM not yet running."

roles/lmn_vm/tasks/main.yml

@@ -144,7 +144,7 @@
   ansible.builtin.copy:
     dest: /etc/tmpfiles.d/clean-vm.conf
     content: |
-      R! /var/tmp/vm
+      D /var/tmp/vm 1777 root root -
 
 - name: Install squid
   apt: