Add `supportingFiles` in Deployment Scripts template

**Is your feature request related to a problem? Please describe.**
I can name a couple of use cases, but I will use two:

- Add packages (`.zip`, `.whl`, etc) in a given Synapse Workspace
- Call a private support file from a script

Both cases above I need to use another file to support the script that Deployment Script is running. In the second use case for example, we have many Powershell scripts with common functions that we keep organized and well structured. So if I run a powershell script I can import that as a module for example. But that doesn't work because only the user script is uploaded to Deployment Script Storage Account. I know there is `supportingScriptUris`, but that only accept `http urls` so that doesn't help much, specially if we have another type of files.

We could maybe try to upload that file to a storage account somehow using Bicep (not easy to do as well), and then trying to retrieve the SAS url, but that would be way hard I would say.

**Describe the solution you'd like**
Create another feature in Deployment Scripts template called `supportingFiles`, which could be an array of local files that could also be uploaded in the same location as user script, that way we can call it way more easily.