Add the nema5-15 version of APC 7900 (#3283)

And update the definition for airflow/weight

Co-authored-by: Karl Quinsland <contact@kquinsland.com>
Co-authored-by: Harry <Harry@cadby.co.uk>

device-types/APC/AP7900B.yaml

@@ -0,0 +1,59 @@
+---
+manufacturer: APC
+# 7900 is NEMA 5-15P, 12A
+# 7901 is NEMA L5-20P, 16A
+# Other than that, they're identical
+model: AP7900B
+slug: apc-ap7900b
+part_number: AP7900B
+u_height: 1
+is_full_depth: false
+airflow: passive
+weight: 2.25
+weight_unit: kg
+comments: |
+  Rack PDU, Switched, 1U, 12A, 120V, (8)5-15
+  [Product Page](https://www.apc.com/us/en/product/AP7900B/apc-netshelter-switched-rack-pdu-1u-1-4kw-120v-15a-8-nema-515r-outlet/)
+console-ports:
+  - name: Serial
+    type: rj-12
+power-ports:
+  - name: Power Port 1
+    type: nema-l5-20p
+power-outlets:
+  - name: Power Outlet 1
+    type: nema-5-15r
+    power_port: Power Port 1
+    feed_leg: A
+  - name: Power Outlet 2
+    type: nema-5-15r
+    power_port: Power Port 1
+    feed_leg: A
+  - name: Power Outlet 3
+    type: nema-5-15r
+    power_port: Power Port 1
+    feed_leg: A
+  - name: Power Outlet 4
+    type: nema-5-15r
+    power_port: Power Port 1
+    feed_leg: A
+  - name: Power Outlet 5
+    type: nema-5-15r
+    power_port: Power Port 1
+    feed_leg: A
+  - name: Power Outlet 6
+    type: nema-5-15r
+    power_port: Power Port 1
+    feed_leg: A
+  - name: Power Outlet 7
+    type: nema-5-15r
+    power_port: Power Port 1
+    feed_leg: A
+  - name: Power Outlet 8
+    type: nema-5-15r
+    power_port: Power Port 1
+    feed_leg: A
+interfaces:
+  - name: Management
+    type: 100base-tx
+    mgmt_only: true