implement before and after config options; remove extra PartialEq, Eq, Hash impl

example/config.toml

@@ -9,6 +9,18 @@ sleep = 1
 # * unset or comment to run once
 # update = 60
 
+# Run specified commands or scripts before and after each queue iteration
+# * `exec` is required
+# * `stdout_contains` is optional
+# * will panic if `stdout_contains` is defined and does not match expected stdout
+# [before]
+    # exec = ""
+    # stdout_contains = [""]
+
+# [after]
+    # exec = ""
+    # stdout_contains = [""]
+
 # Channels queue config
 
 [channel.test]