Enhanced upgrade process and state management

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Infrastructure as Code Type? (Required)

both

### Starter Module? (Required)

not relevant

### Use Case (Required)

As a user of the ALZ Accelerator, I want the bootstrap state to be managed and the update / upgrade process to handle that.

### Proposed Solution (Required)

Options include:

1. Send it up to the storage account we create in the bootstrap.
- This storage account can have a private end point and restricted access. Adding a break out for this would be less than ideal.
2. Create a new storage account with public networking specifically for this purpose. Specify accounts / groups with access

In both cases we need to:

1. Spit out a backend file for the bootstrap.
2. Store and version the input files in blob storage too?
- Would need to make it mandatory to supply sensitive inputs via env var?

Needs some more thought...

Once we have something in place, the upgrade / update process should be able to support remote state.

### Important Factoids (Optional)

_No response_

### References (Optional)

_No response_

Start by reviewing the bootstrap state and the current update/upgrade process, then evaluate the proposed storage-account and blob-storage options. The work is done when bootstrap backend and input-state handling are defined and the upgrade process supports remote state, including the required access and sensitive-input decisions.

Written by the indexing model from the issue text.