debug(ci): set base URL up to be pulled from env

.github/workflows/deploy-storybook.yaml

@@ -42,6 +42,7 @@ jobs:
     runs-on: ubuntu-latest
     env:
       GH_PAGES: true
+      BASE_URL: "/nimbus-gui/"
     needs: cache-dependencies
     steps:
       - uses: actions/checkout@v2

.storybook/main.ts

@@ -19,7 +19,7 @@ const config: StorybookConfig = {
 
   async viteFinal(config, { configType }) {
     if (configType === 'PRODUCTION') {
-      config.base = '/nimbus-gui/'
+      config.base = process.env.BASE_URL || './'
     }
 
     return config