use dotenv in options api

runtimeConfig: {
    public: {
      KEYCLOAK_SCHEME: process.env.KEYCLOAK_SCHEME || 'http',
      KEYCLOAK_HOST: process.env.KEYCLOAK_HOST || 'localhost',
      KEYCLOAK_PORT: process.env.KEYCLOAK_PORT ||'8080',
      KEYCLOAK_CLIENT_ID: process.env.KEYCLOAK_CLIENT_ID || 'testclient',
      KEYCLOAK_REALM: process.env.KEYCLOAK_REALM || 'testrealm'
    },
  }