Add Overland-Tandberg RDX QuikStation 4 (#2095)

* add RDX QuikStation 4

* fix slug on 8920-RDX

* add separate types for 2x1GbE and 4x1Gbe variants

* add elevation images for 8920-rdx

---------

Co-authored-by: Daniel W. Anner <daniel.anner@danstechsupport.com>

device-types/Overland-Tandberg/8920-rdx-2x1gbe.yml

@@ -0,0 +1,18 @@
+---
+manufacturer: Overland-Tandberg
+model: RDX QuikStation 4 (Rackmount, 2x1GbE)
+slug: overland-tandberg-8920-rdx-2x1gbe
+part_number: 8920-RDX 2x1GbE
+u_height: 1
+is_full_depth: true
+weight: 5.98
+weight_unit: kg
+comments: '[RDX QuikStation Product Manual](https://ftp1.overlandtandberg.com/public/TechSupportDocs/External/1021970_D.pdf)'
+power-ports:
+  - name: PSU 1
+    type: iec-60320-c14
+interfaces:
+  - name: Ethernet 1
+    type: 1000base-t
+  - name: Ethernet 2
+    type: 1000base-t

device-types/Overland-Tandberg/8920-rdx-4x1gbe.yml

@@ -0,0 +1,22 @@
+---
+manufacturer: Overland-Tandberg
+model: RDX QuikStation 4 (Rackmount, 4x1GbE)
+slug: overland-tandberg-8920-rdx-4x1gbe
+part_number: 8920-RDX 4x1GbE
+u_height: 1
+is_full_depth: true
+weight: 5.98
+weight_unit: kg
+comments: '[RDX QuikStation Product Manual](https://ftp1.overlandtandberg.com/public/TechSupportDocs/External/1021970_D.pdf)'
+power-ports:
+  - name: PSU 1
+    type: iec-60320-c14
+interfaces:
+  - name: Ethernet 1
+    type: 1000base-t
+  - name: Ethernet 2
+    type: 1000base-t
+  - name: Ethernet 3
+    type: 1000base-t
+  - name: Ethernet 4
+    type: 1000base-t