add network prune

add the ability to prune unused cni networks.  filters are not implemented
but included both compat and podman api endpoints.

Fixes :#8673

Signed-off-by: baude <bbaude@redhat.com>

docs/source/markdown/podman-network-prune.1.md

@@ -0,0 +1,31 @@
+% podman-network-prune(1)
+
+## NAME
+podman\-network\-prune - Remove all unused networks
+
+## SYNOPSIS
+**podman network prune** [*options*]
+
+## DESCRIPTION
+Remove all unused networks.  An unused network is defined by a network which
+has no containers connected or configured to connect to it. It will not remove
+the so-called default network which goes by the name of *podman*.
+
+## OPTIONS
+#### **--force**, **-f**
+
+Do not prompt for confirmation
+
+## EXAMPLE
+Prune networks
+
+```
+podman network prune
+```
+
+
+## SEE ALSO
+podman(1), podman-network(1), podman-network-remove(1)
+
+## HISTORY
+February 2021, Originally compiled by Brent Baude <bbaude@redhat.com>

docs/source/markdown/podman-network.1.md

@@ -19,6 +19,7 @@ The network command manages CNI networks for Podman.
 | exists     | [podman-network-exists(1)](podman-network-exists.1.md)         | Check if the given network exists                                   |
 | inspect    | [podman-network-inspect(1)](podman-network-inspect.1.md)       | Displays the raw CNI network configuration for one or more networks |
 | ls         | [podman-network-ls(1)](podman-network-ls.1.md)                 | Display a summary of CNI networks                                   |
+| prune      | [podman-network-prune(1)](podman-network-prune.1.md)           | Remove all unused networks |
 | reload     | [podman-network-reload(1)](podman-network-reload.1.md)         | Reload network configuration for containers                         |
 | rm         | [podman-network-rm(1)](podman-network-rm.1.md)                 | Remove one or more CNI networks                                     |
 

docs/source/network.rst

@@ -13,6 +13,8 @@ Network
 
 :doc:`ls <markdown/podman-network-ls.1>` network list
 
+:doc:`prune <markdown/podman-network-prune.1>` network prune
+
 :doc:`reload <markdown/podman-network-reload.1>` network reload
 
 :doc:`rm <markdown/podman-network-rm.1>` network rm