Implement permissions/capabilities for plugins

[Nimaoth]

Plugins should only be allowed to perform certain actions when the user gives explicit permission.
The permissions should be very fine grained.

• Running external processes
  • Language servers are a special case probably
  • Allow giving access to specific executables/everything
• Making network connections
  • Specifiy individual hosts/ports
• Accessing the file system
  • Specify read/write access for individual folders/everything
• Reading buffer content
  • Specify permissions per file/folder
  • Permissions:
    • Full content
    • Full content but with secrets replaced by * (depends on Implement secret detection and hiding #18)
    • No access
• Anything else?

Open questions:

• Pass permissions around through functions?
  • (+) Permissions can be handled more fine grained inside plugin (useful if plugin uses libraries)
  • (-) Lots of extra argument
• Or: Specify permissions for entire wasm module
  • (+) Simpler
• Allow passing of permissions between plugins?
  • E.g. Plugin A with permission to read specific folder calls function from plugin B without any permissions but utility functions for reading files and passes it the permission for specific folder