XkOps

Issue

Used helmfile to installed pixie, robusta and kubecost collectively.
Helmfile is used for installing and managing multiple helm charts.
Created the helmfile.yaml, it automatically picks up the helm chart from repository, creates it namespace and deploys them.
Created helmfile hooks for all tools that are executed to perform pre or post steps for successful deployment.
Created a install-helmfile script, the user only needs to run this script and it installs helmfile, give permission to scripts and execute the helmfile.
Created a readme with user guide that users can follow to deploy the tools.
You can read the document to get more information.

[x] Added tests that cover your change (if possible)
[x] Added/modified documentation as required (such as the README.md, or the docs directory)
[x] Manually tested
[x] Made sure the title of the PR is a good description that can go into the release notes (if applicable)
[x] Every function, interface, class has a comment describing what it does and input/output parameters