Implement a CFSSL issuer plugin (#452)

* Implement CFSSL issuer plugin

Implement a Lemur plugin for generating certificates from the open
source certificate authority CFSSL
(https://github.com/cloudflare/cfssl). The plugin interacts with CFSSL
through the CFSSL REST API. The CFSSL configuration is defined in the
lemur.conf.py property file using property names prefixed with "CFSSL_".

* Update documentation to include CFSSL plugin

docs/administration.rst

@@ -361,6 +361,26 @@ for those plugins.
         This is the root to be used for your CA chain
 
 
+CFSSL Issuer Plugin
+^^^^^^^^^^^^^^^^^^^
+
+The following configuration properties are required to use the the CFSSL issuer plugin.
+
+.. data:: CFSSL_URL
+    :noindex:
+
+        This is the URL for the CFSSL API
+
+.. data:: CFSSL_ROOT
+    :noindex:
+
+        This is the root to be used for your CA chain
+
+.. data:: CFSSL_INTERMEDIATE
+    :noindex:
+
+        This is the intermediate to be used for your CA chain
+
 
 AWS Source/Destination Plugin
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -836,6 +856,17 @@ Openssl
     Leverages Openssl to support additional export formats (pkcs12)
 
 
+CFSSL
+-----
+
+:Authors:
+    Charles Hendrie <chad.hendrie@thomsonreuters.com>
+:Type:
+    Issuer
+:Description:
+    Basic support for generating certificates from the private certificate authority CFSSL
+
+
 3rd Party Plugins
 =================
 
@@ -886,4 +917,3 @@ These permissions are applied to the user upon login and refreshed on every requ
 .. seealso::
 
     `Flask-Principal <https://pythonhosted.org/Flask-Principal>`_
-

docs/developer/internals/lemur.plugins.lemur_cfssl.rst

@@ -0,0 +1,20 @@
+lemur_cfssl Package
+===================
+
+:mod:`lemur_cfssl` Package
+--------------------------
+
+.. automodule:: lemur.plugins.lemur_cfssl
+    :noindex:
+    :members:
+    :undoc-members:
+    :show-inheritance:
+
+:mod:`plugin` Module
+--------------------
+
+.. automodule:: lemur.plugins.lemur_cfssl.plugin
+    :noindex:
+    :members:
+    :undoc-members:
+    :show-inheritance:

docs/developer/internals/lemur.plugins.rst

@@ -27,5 +27,6 @@ Subpackages
     lemur.plugins.base
     lemur.plugins.bases
     lemur.plugins.lemur_aws
+    lemur.plugins.lemur_cfssl
     lemur.plugins.lemur_email
     lemur.plugins.lemur_verisign