Use GitHub mermaid.js rendering.

GitHub is now capable of rendering mermaid.js diagrams, so we don't need to maintain a separate source and rendered .png file. The mermaid source can be embedded directly into the documentation itself.

docs/deployment.md

@@ -4,9 +4,40 @@ This guide is deliberately written at a high level and with minimal details
 because it is assumed that VSP operators will already have a level of
 familiarity with Decred software and a level of sysadmin experience.
 
-<p align="center">
-  <img src="./img/architecture.png">
-</p>
+```mermaid
+%%{init:{
+    "theme": "neutral",
+    "themeVariables": {
+        "fontSize": "16px",
+        "clusterBkg": "#E9F8FE",
+        "clusterBorder": "#3D5873",
+        "mainBkg": "#2DD8A3",
+        "primaryColor": "#2970FF"
+    }
+}}%%
+
+graph LR
+
+subgraph Front-end Server
+    nginx(nginx) --> vspd(vspd)
+    vspd --> dcrd0(dcrd)
+end
+
+subgraph voting3 [Voting Server 3]
+    dcrwallet3(dcrwallet) --> dcrd3(dcrd)
+end
+
+subgraph voting2 [Voting Server 2]
+    dcrwallet2(dcrwallet) --> dcrd2(dcrd)
+end
+
+subgraph voting1 [Voting Server 1]
+    dcrwallet1(dcrwallet) --> dcrd1(dcrd)
+end
+
+vspd ----> dcrwallet1 & dcrwallet2 & dcrwallet3
+web(Internet<br />Traffic) ---> nginx
+```
 
 ## Prerequisites
 

docs/img/architecture-source.md

@@ -1,38 +0,0 @@
-Below is the source for architecture.png in mermaid.js syntax.
-
-Can be rendered with any mermaid.js deployment, for example <https://mermaid-js.github.io/mermaid-live-editor/>.
-
-```no-highlight
-%%{init:{
-    "theme": "neutral",
-    "themeVariables": {
-        "fontSize": "16px",
-        "clusterBkg": "#E9F8FE",
-        "clusterBorder": "#3D5873",
-        "mainBkg": "#2DD8A3",
-        "primaryColor": "#2970FF"
-    }
-}}%%
-
-graph LR
-
-subgraph Front-end Server
-    nginx(nginx) --> vspd(vspd)
-    vspd --> dcrd0(dcrd)
-end
-
-subgraph voting3 [Voting Server 3]
-    dcrwallet3(dcrwallet) --> dcrd3(dcrd)
-end
-
-subgraph voting2 [Voting Server 2]
-    dcrwallet2(dcrwallet) --> dcrd2(dcrd)
-end
-
-subgraph voting1 [Voting Server 1]
-    dcrwallet1(dcrwallet) --> dcrd1(dcrd)
-end
-
-vspd ----> dcrwallet1 & dcrwallet2 & dcrwallet3
-web(Internet<br />Traffic) ---> nginx
-```