AIGW Setup script to set FIREWORKS API KEY

What does this merge request do and why?

AIGW Setup script to set FIREWORKS API KEY

Addressing: #2621 (closed)

How to set up and validate locally

1. Checkout this branch in GDK 2621-ai-gw-setup-script-to-update-fireworks-api-key
2. Make a copy of your gitlab-ai-gateway/.env file. For example cp gitlab-ai-gateway/.env ~/ai-gateway-env-backup
3. Reset the current .env file to the default. cp gitlab-ai-gateway/{example.env,.env}
4. Run the rake task rake setup_ai_gateway from the root of GDK. And make sure that it asks you about the Fireworks API
5. After the completion of the setup, check your gitlab-ai-gateway/.env file and make sure it set both Anthropic and Fireworks API Keys to the values you entered in the prompts
6. Restore your old .env file cp ~/ai-gateway-env-backup gitlab-ai-gateway/.env

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This MR references an issue describing the change.
• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.

Closes #2621 (closed)