Support `location = auto` for resourced using bicep params and azd metadata.

> Consider changing region with 'azd env set AZURE_LOCATION ' or requesting a quota increase.
>
> Ideally, I would like azd to look my entire resource-tree and give me the list of locations where I could deploy it all.
>
> The use of templates with one single location for all resources makes it easy to wire things up in bicep/ARM and reduce the number of decisions to make. At the same time, as the number of resources increases, it set customers into a corner to find a valid location for a full set of resources.
>
> I would try to break the idea of one-location-for-all and try to make azd to just find a valid location for each resource. I will create a POC for how that would look like.

_Originally posted by @vhvb1989 in [#6800](https://github.com/Azure/azure-dev/issues/6800#issuecomment-3930549000)_