FEAT: Support editing config from GUI

[Behnam (behnam-o)]

Problem

Previously, changing configuration, environment values, or initializer code in a deployed CoPyRIT instance required direct access to its filesystem, container, or deployment configuration. Changes could also be lost when the container restarted.

This change provides a persistent, browser-based workflow for managing those resources and applying changes without redeploying the application.

Summary

Adds GUI-based management of PyRIT backend configuration, enabling deployed CoPyRIT instances to be configured without direct filesystem or container access.

• Adds support for using a .pyrit_conf Azure Blob Storage in addition to local files.
• Adds backend APIs and a GUI editor for .pyrit_conf (regardless of whether it's a local file or blob)
• Adds backend APIs and a GUI editor for dotenv and Azure Key Vault environment sources.
• Adds support for persisting custom initializer scripts in Azure Blob Storage in addition to the default local path
• Adds GUI for creating and removing custom initializers (backend already exists - just missed a "list" API)
• Updates Docker and Bicep deployment configuration to let us use a custom conf file (to take advantage of the new feature that supports pointing to a blob)
• Updates the docker and deployment configuration to better handle AKV-referenced env vars (instead of letting ARM read the AKV, set its content to an env var, which is then read in start.sh and written to a local file in the container, just let start.sh pass the AKV reference directly in the generate conf file)
• Introduce an admin group, and requires the user be a member of that to access the conf management APIs.

[varunj-msft]

Left a few notes — the video made this much easier to follow! Only two I'd actually give weight on: gui-deploy.yml doesn't pass the new required adminGroupObjectId (param files and deploy_instance.py all got it, just not the pipeline), and a quoted "false" on allow_custom_initializers reads truthy. The rest are minor/follow-up material and non-blocking!

[hannahwestra25]

some of the docs need to be updated including gui.md (being the main one)