Add Prometheus (prometheus.io) to One Click Apps (#203)

* adds logo and oca json for Prometheus monitoring

* run prettier

public/v2/apps/prometheus.json

@@ -0,0 +1,36 @@
+{
+    "captainVersion": "2",
+    "documentation": "https://hub.docker.com/r/prom/prometheus/",
+    "displayName": "Prometheus",
+    "description": "Prometheus is a systems and service monitoring system.",
+    "dockerCompose": {
+        "services": {
+            "$$cap_appname": {
+                "containerHttpPort": "9090",
+                "image": "prom/prometheus@$$cap_version",
+                "restart": "always",
+                "volumes": [
+                    "$$cap_appname-config:/etc/prometheus",
+                    "$$cap_appname-data:/prometheus"
+                ]
+            }
+        },
+        "version": "2",
+        "volumes": {
+            "$$cap_appname-config": {},
+            "$$cap_appname-data": {}
+        }
+    },
+    "instructions": {
+        "end": "Prometheus is now starting.",
+        "start": "Read more about Prometheus: https://prometheus.io/"
+    },
+    "variables": [
+        {
+            "label": "Prometheus Docker Hash",
+            "defaultValue": "sha256:43b19072ef98fd0ea5a29ac794fbadf365cca6d5247830034c7b86ae9650126c",
+            "description": "Starts with 'sha256:'.  Find on Docker Hub.  Default is latest as of 2020-06-30.",
+            "id": "$$cap_version"
+        }
+    ]
+}