Allow multiple deploys from same project

## Description

The hosting property in azure.json is already designed as an enumerable data structure, however only a single configuration can currently be deployed at a time. I.e if I have multiple configs defined in azure.json, only the first has any impact.

Value:
Deploy same project with various build-configurations

Solution:
Change getAzureHostingConfig to return an array of hosting configs rather than finding the first match. Then run deploy on each configuration.

## Type of change

Please delete options that are not relevant.

- [x] New feature (non-breaking change which adds functionality)