Synology rs3621xs+ (#2349)

* add Synology RS3621xs+

* add Synology rs3621xs+

* Fix file issues

* fix slug characters

* Update RS3621xs+.yaml

remove defined "rear-ports". USB-A definition does not exist in schema.

* Update RS3621xs+.yaml

Configured Power ports to PSU bays as this has removable PSUs

---------

Co-authored-by: Harry <Harry@cadby.co.uk>

device-types/Synology/RS3621xs+.yaml

@@ -0,0 +1,41 @@
+---
+manufacturer: Synology
+model: RS3621xs+
+slug: synology-rs3621xs-plus
+part_number: RS3621xs+
+u_height: 2
+is_full_depth: true
+weight: 14.5
+weight_unit: kg
+airflow: front-to-rear
+comments: '[Synology RS3621xs+ Datasheet](https://global.synologydownload.com/download/Document/Hardware/DataSheet/RackStation/21-year/RS3621xs%2B/enu/Synology_RS3621xs%2B_Data_Sheet_enu.pdf)'
+front_image: true
+rear_image: true
+module-bays:
+  - name: PSU-1
+    label: '1'
+    position: PSU-1
+  - name: PSU-2
+    label: '2'
+    position: PSU-2
+interfaces:
+  - name: LAN1
+    type: 1000base-t
+  - name: LAN2
+    type: 1000base-t
+  - name: LAN3
+    type: 1000base-t
+  - name: LAN4
+    type: 1000base-t
+  - name: LAN5
+    type: 10gbase-t
+  - name: LAN6
+    type: 10gbase-t
+  - name: Expansion 1
+    type: infiniband-ndr
+  - name: Expansion 2
+    type: infiniband-ndr
+console-ports:
+  - name: Console
+    type: de-9
+    mgmt_only: true