Be able to point to a hosted APIM instance

**Is your feature request related to a problem? Please describe.**
I'm unable to use static web apps unless I can get it to proxy calls to APIM. I want to be able to point the apiDevserverUrl to an actual APIM instance. For example, I want https://localhost:4200/api/foobar to proxy all calls to https://developers-dev.domain.com/api/foobar

**Describe the solution you'd like**
Be able to specify a url that isn't localhost for the apiDevserverUrl input parameter.

**Describe alternatives you've considered**
There aren't any reasonable solutions.

The issue identifies apiDevserverUrl as the entry point; trace how the CLI uses it for API proxying and review the current localhost handling. Confirm completion by proxying /api/foobar to the specified hosted APIM URL when a non-localhost value is supplied.

Written by the indexing model from the issue text.