Add equipments and topolgies endpoints

- add POST, PUT, DELETE on equipments
- add POST, PUT, GET, DELETE on topogies
- path-computation request body can now have equipment id and/or
topology id instead of full data
- activate embedded https of Flask while waiting for real trusted
certificate
- update readme
- add request payload samples in yang directory
- equipment data are encrypted with Fernet

Signed-off-by: manuedelf <59697943+edelfour@users.noreply.github.com>

gnpy/api/exception/config_error.py

@@ -0,0 +1,14 @@
+# coding: utf-8
+
+
+class ConfigError(Exception):
+    """ Exception raise for configuration file error
+    Attributes:
+        message -- explanation of the error
+    """
+
+    def __init__(self, message):
+        self.message = message
+
+    def __str__(self):
+        return self.message