added external directives to Notifications, change case of keys in host, and update docs

docs/content/cli/exec.md

@@ -15,5 +15,5 @@ The `exec` subcommand can do some things that the configuration file can't do ye
 The commands have to be defined in the config file. The hosts need to at least be in the ssh_config(5) file.
 
 ```sh
-backy exec host [--commands=command1 -commands=command2 ... | -c command1 -c command2 ...] [--hosts=host1 --hosts=hosts2 ... | -m host1 -c host2 ...]  [flags]
+backy exec host [--commands=command1 -commands=command2 ... | -c command1 -c command2 ...] [--hosts=host1 --hosts=hosts2 ... | -m host1 -m host2 ...]  [flags]
 ```

docs/content/cli/list.md

@@ -0,0 +1,29 @@
+---
+title: List
+---
+
+
+List commands, lists, or hosts defined in config file
+
+Usage:
+```
+  backy list [command]
+```
+
+Available Commands:
+  cmds        List commands defined in config file.
+  lists       List lists defined in config file.
+
+Flags:
+```
+  -h, --help   help for list
+```
+
+Global Flags:
+```
+      --cmdStdOut            Pass to print command output to stdout
+  -f, --config string        config file to read from
+      --log-file string      log file to write to
+      --s3-endpoint string   Sets the S3 endpoint used for config file fetching. Overrides S3_ENDPOINT env variable.
+  -v, --verbose              Sets verbose level
+```