Expose getStreamURL for use elsewhere

[tystuyfzand]

Description

getStreamURL in client.go was updated to allow the use of the function outside of the package, for example in an application that handles the http connection itself (with headers, re-connection, etc). It was also updated to allow a context and non-context argument style as the other functions use.

Issues to fix

None

Reminding

Something you can do before PR to reduce time to merge

• run "make build" to build the code (DONE)
• run "make format" to reformat the code (DONE)
• run "make lint" if you are using unix system (Windows)
• run "make test-integration" to pass all tests (Unable to run)

[tystuyfzand]

Looks like the integration tests are failing due to unrelated issues as well.

[Julian-Chu]

Looks like the integration tests are failing due to unrelated issues as well.

Yes, I think PR itself has no problem. I would like to merge it first, and do test after fixing the unrelated issue.

Thanks for the contribution!