Add basic manpages for ctr, containerd, containerd-config

Adds initial manpages for ctr, containerd, and containerd config
commands, as well as the config.toml configuration file.

Adds targets to Makefile for generating and installing manpages.

Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com>

docs/man/ctr.1.md

@@ -0,0 +1,94 @@
+# ctr 1 01/30/2018
+
+## SYNOPSIS
+
+**ctr [global options] command [command options] [arguments...]**
+
+## DESCRIPTION
+
+**ctr** is an unsupported debug and administrative client for interacting
+with the containerd daemon. Because it is unsupported, the commands,
+options, and operation are not guaranteed to be backward compatible or
+stable from release to release of the containerd project.
+
+## OPTIONS
+
+The following commands are available in the **ctr** utility:
+
+**plugins,plugin**
+: Provides information about containerd plugins
+
+**version**
+: Prints the client and server versions
+
+**containers,c,container**
+: Manages and interacts with containers
+
+**content**
+: Manages and interacts with content
+
+**events,event**
+: Displays containerd events
+
+**images,image**
+: Manages and interacts with images
+
+**namespaces,namespace**
+: Manages and interacts with containerd namespaces
+
+**pprof**
+: Provides golang pprof outputs for containerd
+
+**run**
+: Runs a container
+
+**snapshots,snapshot**
+: Manages and interacts with snapshots
+
+**tasks,t,task**
+: Manages and interacts with tasks
+
+**shim**
+: Interacts with a containerd shim directly
+
+**help,h**
+: Displays a list of commands or help for one specific command
+
+The following global options apply to all **ctr** commands:
+
+**--debug**
+: Enable debug output in logs
+
+**--address value, -a value**
+: Address for containerd's GRPC server (default: */run/containerd/containerd.sock*)
+
+**--timeout value**
+: Total timeout for ctr commands (default: *0s*)
+
+**--connect-timeout value**
+: Timeout for connecting to containerd (default: *0s*)
+
+**--namespace value, -n value**
+: Namespace to use with commands (default: *default*) [also read from *$CONTAINERD_NAMESPACE*]
+
+**--help, -h**
+: Show help text
+
+**--version, -v**
+: Prints the **ctr** version
+
+## BUGS
+
+Note that the **ctr** utility is not an officially supported part of the
+containerd project releases.
+
+However, please feel free to file any specific issues that you encounter at
+https://github.com/containerd/containerd.
+
+## AUTHOR
+
+Phil Estes <estesp@gmail.com>
+
+## SEE ALSO
+
+containerd(1), config.toml(5), containerd-config(1)