Add custom ExitAfterRedirect sniff and ruleset configuration

[bordoni]

Now when you do wp_redirect or wp_safe_redirect calls, you can use tribe_exit() or tec_exit()

[borkweb]

I don't think this should be in the StellarWP sniffs or ruleset. Now is the time to create an official TEC set of Sniffs and ruleset in this repo rather than having the TEC dir as a symlink. The TEC ruleset should extend the StellarWP ones.