Demo frontend follow-ups (#1926)

* Demo frontend follow-ups

### What's done:
 * Added backend endpoints that check permissions and forward them to save-demo (for /start and /stop)
 * Finished frontend menu
 * Tested locally on !kubernetes profile
 * Slightly refactored DemoManagerController

(#1925)

Author: sanyavertolet

save-backend/backend-api-docs.json

@@ -2107,6 +2107,74 @@
         ]
       }
     },
+    "/api/v1/demo/{organizationName}/{projectName}/start": {
+      "post": {
+        "description": "Start demo container if possible, do nothing otherwise.",
+        "operationId": "startDemo",
+        "parameters": [
+          {
+            "description": "name of saveourtool organization",
+            "in": "path",
+            "name": "organizationName",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          },
+          {
+            "description": "name of saveourtool project",
+            "in": "path",
+            "name": "projectName",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          },
+          {
+            "example": "basic",
+            "in": "header",
+            "name": "X-Authorization-Source",
+            "required": true
+          }
+        ],
+        "responses": {
+          "200": {
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            },
+            "description": "Successfully started demo."
+          },
+          "403": {
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            },
+            "description": "Not enough permission for demo management."
+          },
+          "404": {
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            },
+            "description": "Could not find saveourtool project or demo of a project."
+          }
+        },
+        "summary": "Start demo container.",
+        "tags": [
+          "demo-manager-controller"
+        ]
+      }
+    },
     "/api/v1/demo/{organizationName}/{projectName}/status": {
       "get": {
         "description": "Get demo status.",
@@ -2148,7 +2216,8 @@
                     "NOT_CREATED",
                     "RUNNING",
                     "STARTING",
-                    "STOPPED"
+                    "STOPPED",
+                    "STOPPING"
                   ]
                 }
               }
@@ -2165,7 +2234,8 @@
                     "NOT_CREATED",
                     "RUNNING",
                     "STARTING",
-                    "STOPPED"
+                    "STOPPED",
+                    "STOPPING"
                   ]
                 }
               }
@@ -2182,7 +2252,8 @@
                     "NOT_CREATED",
                     "RUNNING",
                     "STARTING",
-                    "STOPPED"
+                    "STOPPED",
+                    "STOPPING"
                   ]
                 }
               }
@@ -2196,6 +2267,74 @@
         ]
       }
     },
+    "/api/v1/demo/{organizationName}/{projectName}/stop": {
+      "post": {
+        "description": "Delete demo container if possible, do nothing otherwise.",
+        "operationId": "stopDemo",
+        "parameters": [
+          {
+            "description": "name of saveourtool organization",
+            "in": "path",
+            "name": "organizationName",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          },
+          {
+            "description": "name of saveourtool project",
+            "in": "path",
+            "name": "projectName",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          },
+          {
+            "example": "basic",
+            "in": "header",
+            "name": "X-Authorization-Source",
+            "required": true
+          }
+        ],
+        "responses": {
+          "200": {
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            },
+            "description": "Successfully stopped demo."
+          },
+          "403": {
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            },
+            "description": "Not enough permission for demo management."
+          },
+          "404": {
+            "content": {
+              "*/*": {
+                "schema": {
+                  "type": "string"
+                }
+              }
+            },
+            "description": "Could not find saveourtool project or demo of a project."
+          }
+        },
+        "summary": "Stop demo.",
+        "tags": [
+          "demo-manager-controller"
+        ]
+      }
+    },
     "/api/v1/demo/{organizationName}/{projectName}/upload-file": {
       "post": {
         "description": "Attach file to demo.",
@@ -8379,7 +8518,8 @@
               "NOT_CREATED",
               "RUNNING",
               "STARTING",
-              "STOPPED"
+              "STOPPED",
+              "STOPPING"
             ]
           }
         }