adding Watchguard T45 (#3050)

* adding Watchguard T45

* fixed merge issues: created rackmount for device-bay, removed rear ports

* fixed slug issue with Rackmount.IT

* Update Firebox-T45.yaml

* Update RM-WG-T6.yaml

---------

Co-authored-by: Marco Dieckhoff <marco.dieckhoff@gmail.com>
Co-authored-by: Harry <Harry@cadby.co.uk>

device-types/Rackmount IT/RM-WG-T6.yaml

@@ -0,0 +1,13 @@
+---
+manufacturer: Rackmount IT
+model: RM-WG-T6
+slug: rackmount-it-rm-wg-t6
+u_height: 1
+subdevice_role: parent
+is_full_depth: false
+is_powered: false
+airflow: passive
+comments: Holds Watchguard T20, T25, T40 and T45
+front_image: true
+device-bays:
+  - name: Watchguard device

device-types/WatchGuard/Firebox-T45.yaml

@@ -0,0 +1,30 @@
+---
+manufacturer: WatchGuard
+model: Firebox T45
+slug: watchguard-firebox-t45
+u_height: 0
+subdevice_role: child
+is_full_depth: false
+airflow: left-to-right
+comments: '[Watchguard Firebox T45 Hardware Guide](https://www.watchguard.com/help/docs/help-center/en-US/Content/en-US/Hardware-Guides/firebox-t45-hardware-guide.html)'
+front_image: true
+rear_image: true
+weight: 0.88
+weight_unit: kg
+console-ports:
+  - name: mgmnt
+    type: rj-45
+power-ports:
+  - name: PSU0
+    type: dc-terminal
+interfaces:
+  - name: eth0
+    type: 1000base-t
+  - name: eth1
+    type: 1000base-t
+  - name: eth2
+    type: 1000base-t
+  - name: eth3
+    type: 1000base-t
+  - name: eth4
+    type: 1000base-t