Enabled and Disabled tools configuration

[manusa]

Description

As a user/mcp admin, I want to be able provide a list of allowed or denied tools, so that I can configure which tools are accessible to the AI assistant/agent.

• Configuration (toml) contains the following fields
• allowed_tools enabled_tools (slice/array)
  • If empty, all tools are available
  • If NOT empty, only tools configured are available
• denied_tools disabled_tools
  • If empty, NO OP
  • If NOT empty, tools configured are explicitly removed from the list of available tools

Originally defined by @ardaguclu in #155