News features and improvements (#8)

* added config file implementation, refactoring

* add gitignore

* improved test

* preperations for more metrics

* added resource metrics

* added first bgp metrics

* added asn as label for bgp metrics

* added prefix and message counts to bgp metrics

* simplified

* Update README.md

* added yaml dependency

* fixed go routine call

* added timeout

* clean up

* added TLS support

* set default api port for TLS

* added routes metric

* added missing log information

config/test/config.test.yml

@@ -0,0 +1,11 @@
+---
+
+devices:
+  - name: test1
+    address: 192.168.1.1
+    user: foo
+    password: bar
+  - name: test2
+    address: 192.168.2.1
+    user: test
+    password: 123