Add MCP tools for creating proxy hosts and listing access lists, with configurable defaults via environment variable.
New tools:
- create_proxy_host: Create new proxy hosts with SSL, access control, and websocket support
- list_access_lists: List available access lists for use in proxy host creation
New features:
- NPM_PROXY_DEFAULTS env var for configurable default values (certificate_id, access_list_id, ssl settings, etc.)
