chore: Add localdev to performance tests (#1682)

<!--- Provide a general summary of your changes in the Title above -->

## Description

<!--- Describe your changes in detail -->

## Related Issue(s)

- #{issue number}

## Verification

- [ ] **Your** code builds clean without any errors or warnings
- [ ] Manual testing done (required)
- [ ] Relevant automated test added (if you find this hard, leave it and
we'll help out)

## Documentation

- [ ] Documentation is updated (either in `docs`-directory, Altinnpedia
or a separate linked PR in
[altinn-studio-docs.](https://github.com/Altinn/altinn-studio-docs), if
applicable)

tests/k6/tests/performancetest_data/endusers-localdev.csv

@@ -0,0 +1,2 @@
+ssn,resource,scopes
+08895699684,super-simple-service,digdir:dialogporten

tests/k6/tests/performancetest_data/serviceowners-localdev.csv

@@ -0,0 +1,3 @@
+org,orgno,scopes,resource
+digdir,991825827,digdir:dialogporten.serviceprovider digdir:dialogporten.serviceprovider.search,super-simple-service
+nav,889640782,digdir:dialogporten.serviceprovider digdir:dialogporten.serviceprovider.search digdir:dialogporten.serviceprovider.legacyhtml altinn:system/notifications.condition.check digdir:dialogporten.correspondence

tests/k6/tests/scripts/generate_tokens.sh

@@ -33,6 +33,8 @@ case $API_ENVIRONMENT in
         env="tt02" ;;
     "yt01")
         env="yt01" ;;
+    "localdev")
+        env="at21" ;;
     *)
         echo "Error: Unknown api environment $API_ENVIRONMENT"
         exit 1 ;;