Setup Firebase skeleton

[kevinkiklee]

This PR integrates the FLEDGE demo with Firebase for hosting.

(Please do not review the code around FLEDGE logic as they will be updated in the future)

Hostnames

Production

• Main - https://fledge-demo.web.app/
• Advertiser - https://fledge-demo-advertiser.web.app/
• Publisher- https://fledge-demo-publisher.web.app/
• DSP - https://fledge-demo-dsp.web.app/
• SSP - https://fledge-demo-ssp.web.app/

Local

• Main - https://localhost:8080
• Advertiser - https://localhost:8085
• Publisher - https://localhost:8086
• DSP - https://localhost:8087
• SSP - https://localhost:8088