engine: Resources package rewrite

This giant patch makes some much needed improvements to the code base.

* The engine has been rewritten and lives within engine/graph/
* All of the common interfaces and code now live in engine/
* All of the resources are in one package called engine/resources/
* The Res API can use different "traits" from engine/traits/
* The Res API has been simplified to hide many of the old internals
* The Watch & Process loops were previously inverted, but is now fixed
* The likelihood of package cycles has been reduced drastically
* And much, much more...

Unfortunately, some code had to be temporarily removed. The remote code
had to be taken out, as did the prometheus code. We hope to have these
back in new forms as soon as possible.

test/shell/graph-exit1.sh

@@ -2,9 +2,11 @@
 
 # should take 15 seconds for longest resources plus startup time to shutdown
 # we don't want the ^C to allow the rest of the graph to continue executing!
-$timeout --kill-after=65s 55s "$MGMT" run --yaml graph-exit1.yaml --no-watch --no-pgp --tmp-prefix &
+# this is a test of mgmt exiting quickly via a fast pause after it sees a ^C
+$timeout --kill-after=60s 55s "$MGMT" run --yaml graph-exit1.yaml --no-watch --no-pgp --tmp-prefix &
 pid=$!
 sleep 5s	# let the initial resources start to run...
 killall -SIGINT mgmt	# send ^C to exit mgmt
+killall -SIGINT mgmt	# send a second ^C to activate fast pause
 wait $pid	# get exit status
 exit $?