dnsmasq: store leases in sqlite database

To avoid dnsmasq writing out the whole leasefile on each request
before replying. This gets slow on high‐latency storage.

Also tweak DNS updates a bit.

roles/dnsmasq/tasks/main.yml

@@ -2,9 +2,10 @@
   package:
     name:
     - dnsmasq
-    - bind-tools
-    - krb5
-    - py3-pexpect
+    - bind-tools # for DNS updates
+    - krb5 # for DNS updates
+    - py3-pexpect # for creating kerberos keytab
+    - sqlite # for lease DB
 
 - name: Configure kerberos
   template:
@@ -23,11 +24,11 @@
   args:
     creates: /etc/krb5.keytab
 
-- name: Copy DNS updater script
+- name: Copy DHCP lease script
   template:
-    dest: "/usr/local/bin/dns-update"
-    src: "dns-update.j2"
-    mode: 0700
+    dest: "/usr/local/bin/dnsmasq-script"
+    src: "dnsmasq-script.j2"
+    mode: 0755
 
 - name: Configure dnsmasq
   template: