Add bridge_mtu config to docs

docs/manuals/daemon.md

@@ -146,6 +146,7 @@ pvc:
         console_log_lines: 1000
       networking:
         bridge_device: ens4
+        bridge_mtu: 1500
         sriov_enable: True
         sriov_device:
           - phy: ens1f0
@@ -427,6 +428,13 @@ How many lines of VM console logs to keep in the Zookeeper database for each VM.
 
 The network interface device used to create Bridged client network vLANs on. For most clusters, should match the underlying device of the various static networks (e.g. `ens4` or `bond0`), though may also use a separate network interface.
 
+#### `system` → `configuration` → `networking` → `bridge_mtu`
+
+* *optional*
+* *requires* `functions` → `enable_networking`
+
+The network interface MTU for the Bridged client network device. This is the maximum MTU a bridged client network can use.
+
 #### `system` → `configuration` → `networking` → `sriov_enable`
 
 * *optional*, defaults to `False`