middleware.cfg to configure middleware directives (#496)

* Use go generate to build middleware setup based on middleware.cfg
Init default config

* generated files

* Move gen to an isolated area

* rename files

* PR review updates

* undo readme

middleware.cfg

@@ -0,0 +1,43 @@
+# Directives are registered in the order they should be
+# executed.
+#
+# Ordering is VERY important. Every middleware will
+# feel the effects of all other middleware below
+# (after) them during a request, but they must not
+# care what middleware above them are doing.
+
+
+# How to rebuild with updated middleware configurations:
+# Modify the list below and run `make gen && make`
+
+# The parser takes the input format of
+#     <order>:<middleware-name>:<package-name>
+# OR
+#     <order>:<middleware-name>:
+# External middleware example:
+# 80:log:github.com/miekg/coredns/middleware/log
+# Local middleware example:
+# 80:log:
+
+10:root:
+20:bind:
+30:trace:
+40:health:
+50:pprof:
+60:prometheus:
+70:errors:
+80:log:
+90:chaos:
+100:cache:
+110:rewrite:
+120:loadbalance:
+130:dnssec:
+140:file:
+150:auto:
+160:secondary:
+170:etcd:
+180:kubernetes:
+190:proxy:
+200:httpprox:
+210:whoami:
+220:erratic: