Add Meinberg Lantime M300 (#2475)

* Add Meinberg Lantime M300

* yamllint fixes

* Fixing issues raised by review

* Add weight

* Add max power consumption to PSU

* rename the image to be found

* Update elevation image, removed second psu to corespond with elevation image

device-types/Meinberg/lantime-m300.yml

@@ -0,0 +1,32 @@
+---
+manufacturer: Meinberg
+model: Lantime M300
+slug: meinberg-lantime-m300
+description: NTP Server in 1U Case for Server Rackmount
+u_height: 1.0
+is_full_depth: false
+airflow: passive
+front_image: true
+rear_image: true
+comments: '[Product Page](https://www.meinbergglobal.com/english/archive/lantime-m300.htm)'
+weight: 3.5
+weight_unit: kg
+console-ports:
+  - name: serial
+    type: de-9
+    label: Terminal
+power-ports:
+  - name: PWR1
+    type: iec-60320-c14
+    maximum_draw: 20
+interfaces:
+  - name: lan0
+    type: 100base-tx
+    enabled: true
+    mgmt_only: false
+    label: LAN0
+  - name: lan1
+    type: 1000base-tx
+    enabled: true
+    mgmt_only: false
+    label: LAN1