Add utility APIs and add brief return fields and pagination

[arthanson]

• Adds new tools for AI Agent:
  • netbox_get_valid_filters
  • netbox_get_fields
  • netbox_slugify_name

These utility functions can be used by the API to get what parameters to pass to other APIs as the documentation can be out of sync with the version of netbox being used. Also reduces the context data that needs to be sent to the UI (i.e. not sending one big table of all apis, filters, etc..

• Returns brief API by default to limit amount of data for AI agent

• Adds pagination

• Adds a contents.py that contains a dictionary used for these APIs that specify what filters, fields, etc. are available. Note: This is somewhat version specific to NetBox

• Also add CODEOWNERS file for auto review assignment.

[beevek]

Thanks @arthanson - couple questions:

• I think now we are not passing a list of object types to the LLM in any of the MCP tools' docs (just giving the very brief example in netbox_get_objects of "devices", "ip-addresses"). Main worry I have with this is the LLM may not have a complete understanding of the available object types for all the tools. Should we add a get_object_types tool? Or re-inject a list of object types in the docs of one of the tools?
• Do we need netbox_slugify_name to be an MCP tool? Is it mainly used to sanitize params for other tools (in which case, can we just call it inside the appropriate tool calls)? Just trying to have a predilection for minimizing the number of tools (to maximize effectiveness in using them).