Add prometheus metrics for Central controllers (#1969)

* add header-only prometheus lib to ext

* rename folder

* Undo rename directory

* prometheus simpleapi included on mac & linux

* wip

* wire up some controller stats

* Get windows building with prometheus

* bsd build flags for prometheus

* Fix multiple network join from environment entrypoint.sh.release (#1961)

* _bond_m guards _bond, not _paths_m (#1965)

* Fix: warning: mutex '_aqm_m' is not held on every path through here [-Wthread-safety-analysis] (#1964)

* Serve prom metrics from /metrics endpoint

* Add prom metrics for Central controller specific things

* reorganize metric initialization

* testing out a labled gauge on Networks

* increment error counter on throw

* Consolidate metrics definitions

Put all metric definitions into node/Metrics.hpp.  Accessed as needed
from there.

* Revert "testing out a labled gauge on Networks"

This reverts commit 499ed6d95e11452019cdf48e32ed4cd878c2705b.

* still blows up but adding to the record for completeness right now

* Fix runtime issues with metrics

* Add metrics files to visual studio project

* Missed an "extern"

* add copyright headers to new files

* Add metrics for sent/received bytes (total)

* put /metrics endpoint behind auth

* sendto returns int on Win32

---------

Co-authored-by: Leonardo Amaral <leleobhz@users.noreply.github.com>
Co-authored-by: Brenton Bostick <bostick@gmail.com>

ext/prometheus-cpp-lite-1.0/CMakeLists.txt

@@ -0,0 +1,34 @@
+project(prometheus-cpp-lite)
+cmake_minimum_required(VERSION 3.2)
+
+option(PROMETHEUS_BUILD_EXAMPLES "Build with examples" OFF)
+
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_SOURCE_DIR}/bin)
+
+if(WIN32) 
+
+  # it prevent create Debug/ and Release folders in Visual Studio
+  foreach( OUTPUTCONFIG ${CMAKE_CONFIGURATION_TYPES} )
+    string( TOUPPER ${OUTPUTCONFIG} OUTPUTCONFIG )
+    set( CMAKE_RUNTIME_OUTPUT_DIRECTORY_${OUTPUTCONFIG} ${PROJECT_SOURCE_DIR}/bin )
+  endforeach()
+
+  set (INSTALL_PATH_BIN "${PROJECT_SOURCE_DIR}/installed/bin/")
+
+else() # not WIN32
+
+  set (INSTALL_PATH_BIN "bin/")
+
+endif()
+
+add_subdirectory("./core")
+
+add_subdirectory("./simpleapi")
+
+add_subdirectory("./3rdpatry/http-client-lite")
+
+if(PROMETHEUS_BUILD_EXAMPLES)
+  add_subdirectory("./examples")
+endif()
+
+