feat: initial Prometheus analyzers

[pintohutch]

Closes #

📑 Description

Added a prometheus integration with two analyzers:

1. PrometheusConfigValidate
2. PrometheusConfigRelabelReport

The integration does not deploy any Prometheus stack in the cluster.
Instead, it searches the provided --namespace for a Prometheus
configuration, stored in a ConfigMap or Secret. If it finds one, it
unmarshals it into memory and runs the analyzers on it.

PrometheusConfigValidate checks if the actual Prometheus configuration is valid or has
any errors.

PrometheusConfigRelabelReport tries to distill the scrape config
relabeling rules to give a concise label set per job that targets need
to have to be scraped. This analyzer is unconventional, in that it does
not necessarily mean there are issues with the config. It merely tries
to give a human-readable explanation of the relabel rules it discovers,
leaning on the LLM and prompt.

Tested on both kube-prometheus and Google Managed Prometheus
stacks.

✅ Checks

• My pull request adheres to the code style of this project
• My code requires changes to the documentation
• I have updated the documentation as required
• All the tests have passed

ℹ Additional Information

[pintohutch]

Quick demo:

k8sgpt-prom-demo.mov

The output isn't perfect. I'm betting we can improve with a better prompt...

[pintohutch]

Also for the PrometheusConfigRelabelReport analyzer, the entire relabel config is inserted into the prompt. This may not be ideal and prints a verbose "error" message.

Maybe there's a better way to do this as well.

[matthisholleville]

Thank you for this awesome contribution 🤩 . I'm really excited to add this integration. Left some comments

[pintohutch]

Thanks @matthisholleville - pushed some changes per your comments!

[AlexsJones]

Overall comment - great contribution and thank you for helping us figure out what we want integrations to be. I am glad the pattern itself is holding up okay and kudos to figuring it out.

I do think there should be some guard rails if you go run main.go integration activate prometheus without having prometheus installed -perhaps use the Deploy() function to check if there is a prometheus pod in the namespace with a simple regex? At least have a warning message if we don't find something.

In future, ( maybe kubecon ) the contributors need to talk about that wider vision of how integrations will look - I am very excited to have a Prometheus component though.

[pintohutch]

Demo:
https://github.com/k8sgpt-ai/k8sgpt/assets/3731548/bafcec60-b772-4d5d-8288-a9511fdef3ac

Thanks @AlexsJones - added the functionality to Deploy() per suggestion and included some logging and comments with context.

[matthisholleville]

LGTM