Certificates Renewal + SSE

- Certificate renewal is just a re-request as it's forced already
- Rejig the routes for readability
- Added Server Side Events so that the UI would invalidate the
cache when changes happen on the backend, such as certs being
provided or failing
- Added a SSE Token, which has the same shelf life as normal token
but can't be used interchangeably. The reason for this is, the
SSE endpoint needs a token for auth as a Query param, so it would
be stored in log files. If someone where to get a hold of that,
it's pretty useless as it can't be used to change anything, only
to listen for events until it expires
- Added test endpoint for SSE testing only availabe in debug mode

backend/embed/api_docs/paths/tokens/sse/post.json

@@ -0,0 +1,33 @@
+{
+	"operationId": "requestSSEToken",
+	"summary": "Request a new SSE token",
+	"tags": ["Tokens"],
+	"responses": {
+		"200": {
+			"description": "200 response",
+			"content": {
+				"application/json": {
+					"schema": {
+						"required": ["result"],
+						"properties": {
+							"result": {
+								"$ref": "#/components/schemas/TokenObject"
+							}
+						}
+					},
+					"examples": {
+						"default": {
+							"value": {
+								"result": {
+									"expires": 1566540510,
+									"token": "eyJhbGciOiJSUzUxMiIsInR5cCI6IkpXVCJ9.ey...xaHKYr3Kk6MvkUjcC4",
+									"scope": "user"
+								}
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+}