POC: Allow OpenAI to execute arbitrary external actions + no-code implementation with N8N

[nickmisasi]

Closes #

Description

[azigler]

See https://hub.mattermost.com/private-core/pl/4187hrmagiykxct438ksh6uzoa for context

[azigler]

See Confluence for demos and resources around this POC.

https://mattermost.atlassian.net/wiki/spaces/FF/pages/2810019862/Toolkits

[azigler]

This latest merge to master to incorporate #208 needs a revisit. Currently this branch isn't properly supplying the list of available tools in the base prompt, so it's not doing any function calling. I think I messed up the merge somewhere in ai/openai/openai.go in the toolsToOpenAITools function.

{
  "caller": "app/plugin_api.go:1004",
  "level": "info",
  "msg": "LLM Call",
  "plugin_id": "mattermost-ai",
  "prompt": "\n--- Conversation ---\n--- System ---\nYou are a helpful assistant called \"Copilot\" that responds on a Mattermost chat server called Mattermost owned by .\n\nCurrent time and date in the user's location is Wed, 26 Jun 2024 15:29:06 PDT\n\nThe following is the personal information of the user. This information is given with every request to you. You can use this information to taylor the request to the specific user however most of the time it will not be relavent. Only acknowledge the information when the request is directly related to the information provided. Never repeat it as written.\nThe user making the request username is 'admin'.\n\n\n\n\nThe channel you are responding in has the name 'town-square' and display name 'Town Square'. The channel is on a team called 'test' with display name 'test'.\n--- User ---\n@ai What tools can you use?\n--- Tools ---\n\n--- Context ---\nTime: Wed, 26 Jun 2024 15:29:06 PDT\nServerName: Mattermost\nCompanyName: \nRequestingUser: admin\nChannel: town-square\nTeam: test\nPost: 61funp1ry7y67jcgbp6qigjyoy\nPromptParameters:\n",
  "timestamp": "2024-06-26 22:29:06.269 Z"
}