[FR]: Proxy settings

[UzverNumber47]

Description

1. Add the ability to proxy every request to api
2. Can't find how it can be done right now
3. Idially it should be something similar to the Android version
   System.setProperty("https.proxyHost", "x.x.x.x"); System.setProperty("https.proxyPort", "nnnn"); System.setProperty("com.google.api.client.should_use_proxy", "true");

API Proposal

No response

Firebase Product(s)

Database

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[triplef]

Partial duplicate of #11858.