[DRAFT] feat(agent): uniget ui broker implementation

[Vladyslav Nikonov (vnikonov-devolutions)]

Implements now package broker (Also see UniGetUI WIP branch Devolutions/UniGetUI#4826)

This is still in early DRAFT, but can be compiled/tested for further development.

Implemented

• Policy parsing (both json and yaml), evaluation, JSON scheme generation.
• Dry-run executor
• Windows executor/command builder for winget & PowerShell; needs refining but implements most of the functionality
• Elevated/non elevated execution with user impersonation.
• Made some updated to initial PoC schema - cleaned up, renamed and restructured some fields, added new request/response for polling operation status

Not implemented yet

• ACL-based security for pipes, signature check
• Other managers except winget and powershell

Steps to run this branch:

• Compile and replace DevolutionsAgent.exe from this branch.
• Add new agent config fields:
  "PackageBroker":{"Enabled":true, "PolicyPath": "C:/path/to/policy.json"}
• Create empty UseAgentBroker file at %LOCALAPPDATA%/UniGetUI/Configuration (UniGetUI uses file-based config)
• Start Agent
• Start UniGetUI, test

[github-actions]

Let maintainers know that an action is required on their side

• Add the label release-required Please cut a new release (Devolutions Gateway, Devolutions Agent, Jetsocat, PowerShell module) when you request a maintainer to cut a new release (Devolutions Gateway, Devolutions Agent, Jetsocat, PowerShell module)

• Add the label release-blocker Follow-up is required before cutting a new release if a follow-up is required before cutting a new release

• Add the label publish-required Please publish libraries (`Devolutions.Gateway.Utils`, OpenAPI clients, etc) when you request a maintainer to publish libraries (Devolutions.Gateway.Utils, OpenAPI clients, etc.)

• Add the label publish-blocker Follow-up is required before publishing libraries if a follow-up is required before publishing libraries