add `install` subcommand to `uffizzi -h`

[gadkins]

Summary

Add install as a subcommand in the uffizzi help page

uffizzi -h
uffizzi - manage Uffizzi resources
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## SYNOPSIS
    uffizzi GROUP | COMMAND

## DESCRIPTION
    The uffizzi CLI manages authentication, configuration, and
    interaction with Uffizzi APIs.

    For more information on the uffizzi CLI, see:
    https://docs.uffizzi.com/references/cli/

## GROUP
    GROUP is one of the following:
     cluster
         Manage virtual clusters

     config
         Configure the uffizzi CLI

     connect
         Grant a Uffizzi user account access to external services

     compose
         Manage Uffizzi compose environments (previews) and view logs

     dev
         Creates a Uffizzi cluster preconfigured for development workflows

     install
         Install Uffizzi data plane on a Kubernetes cluster

     project
         Manage Uffizzi project resources including compose files for
         specifying compose environment (preview) configurations and secrets
...