feat: add API_KEY list support

[neboman11]

Description

This PR fixes #729 and #480

This PR is a copy of #740 but with the API key option changed to a list (as requested in that PR).

This PR adds api-key flag. When this flag is set, all API requests needs to provide the same value as Bear token in the request hear. If this flag is not set, no auth will be enabled. This flag is not set by default.

Notes for Reviewers

Signed commits

• Yes, I signed my commits.

[mudler]

Looking good here, thanks!

[luisfarzati]

@neboman11 you rock ❤️ thank you!

[alexander-potemkin]

I'm sorry, and how does it work with models/available endpoint?

I'm having problems checking for the models available:

# curl http://localhost:8080/models/available -H "Authorization: Bearer $myApiKey"
{"message":"Invalid API key"}

[alexander-potemkin]

btw, same when I try to query the model, by using default's OpenAI's example:

curl http://localhost:8080/v1/chat/completions   -H "Content-Type: application/json"   -H "Authorization: Bearer $myApiKey"   -d '{
    "model": "gpt-3.5-turbo",
    "messages": [
      {
        "role": "system",
        "content": "You are a poetic assistant, skilled in explaining complex programming concepts with creative flair."
      },
      {
        "role": "user",
        "content": "Compose a poem that explains the concept of recursion in programming."
      }
    ]
  }'
{"message":"Invalid API key"}

[alexander-potemkin]

Please, forgive me - I shouldn't been adding quotes for the key in my docker-compose.yml.