Refactor docs into mdbook (#547)

* Refactor documentation, ef_tests makefile

* Add makefile to root

* Tidy readme

* Fix readme badges

* Tidy logs

* Add terminalize gif

* Update readme image

* Update readme image

* Tidy logs

* Update readme image

* Update readme

* Update readme

* Fix book link

* Update makefiles

* Update book

* Fix link in book

* Add readme for book

* Remove old docs, move api spec YAML

* Fix eth2/ dir readme

* Add readme for lcli

* Add about this book section

* Minor formatting improvements

* Address mehdi's comments

book/src/api.md

@@ -0,0 +1,13 @@
+# APIs
+
+The Lighthouse `beacon_node` provides two APIs for local consumption:
+
+- A [RESTful JSON HTTP API](http.html) which provides beacon chain, node and network
+	information.
+- A read-only [WebSocket API](websockets.html) providing beacon chain events, as they occur.
+
+
+## Security
+
+These endpoints are not designed to be exposed to the public Internet or
+untrusted users. They may pose a considerable DoS attack vector when used improperly.