Added architecture diagram (#1180)

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

docs/Architecture/Overview.md

@@ -0,0 +1,10 @@
+description: Pantheon Architecture 
+<!--- END of page meta data -->
+
+# Pantheon Architecture
+
+The high-level architecture of Pantheon is: 
+
+![Architecture](../images/Architecture.png)
+
+If you've got questions about the architecture of Pantheon, contact us on [gitter](https://gitter.im/PegaSysEng/pantheon). 

docs/Reference/JSON-RPC-API-Methods.md

@@ -20,7 +20,7 @@ description: Pantheon JSON-RPC API methods reference
 Adds a [static node](../Configuring-Pantheon/Networking/Managing-Peers.md#static-nodes).  
 
 !!! caution 
-    If connections are timing out, ensure the node ID in the [enode URL](../Node-Keys.md#enode-url) is correct. 
+    If connections are timing out, ensure the node ID in the [enode URL](../Configuring-Pantheon/Node-Keys.md#enode-url) is correct. 
 
 **Parameters**
 
@@ -189,7 +189,7 @@ Removes a [static node](../Configuring-Pantheon/Networking/Managing-Peers.md#sta
 
 **Returns**
 
-`result` : `boolean` - `true` if peer removed or `false` if peer not a [static node]((../Configuring-Pantheon/Networking/Managing-Peers.md#static-nodes)). 
+`result` : `boolean` - `true` if peer removed or `false` if peer not a [static node](../Configuring-Pantheon/Networking/Managing-Peers.md#static-nodes)). 
 
 !!! example
     ```bash tab="curl HTTP request"

docs/architecture/architecture.md

@@ -1,3 +0,0 @@
-**TODO:**
-
-## Attribution

mkdocs.yml

@@ -46,6 +46,8 @@ nav:
         - Installation Overview: Installation/Overview.md
         - Install Binary Distribution: Installation/Install-Binaries.md
         - Build from Source: Installation/Build-From-Source.md
+    - Architecture:
+        - Overview: Architecture/Overview.md
     - Getting Started:
         - Getting Started Overview: Getting-Started/Getting-Started.md
         - Starting Pantheon: Getting-Started/Starting-Pantheon.md