DHCP Lease Collector (#50)

* DHCP Leases Collector

Add Information about DHCP Leases:
* Active MAC Address
* Active Address
* Hostname
* Status
* Expire time

* Modified resource collector

Add Boardname and RouterOS version metrics

config/config.test.yml

@@ -0,0 +1,20 @@
+devices:
+  - name: test1
+    address: 192.168.1.1
+    user: foo
+    password: bar
+  - name: test2
+    address: 192.168.2.1
+    user: test
+    password: 123
+
+features:
+  bgp: true
+  dhcp: true
+  dhcpv6: true
+  dhcpl: true
+  routes: true
+  pools: true
+  optics: true
+  wlansta: true
+  wlanif: true