Update the tanzu context create command help

[prkalle]

What this PR does / why we need it

This PR updates tanzu context create command help to include guidance on utilizing TANZU_API_TOKEN and TANZU_CLI_CLOUD_SERVICES_ORGANIZATION_ID environment variables during context creation.

Which issue(s) this PR fixes

Fixes #

Describe testing done for PR

The tanzu context create command help shows the below help

❯ ./bin/tanzu context create -h
Create a Tanzu CLI context

Usage:
  tanzu context create CONTEXT_NAME [flags]

Examples:

    # Create a TKG management cluster context using endpoint and type (--type is optional, if not provided the CLI will infer the type from the endpoint)
    tanzu context create mgmt-cluster --endpoint https://k8s.example.com[:port] --type k8s

    # Create a TKG management cluster context using endpoint
    tanzu context create mgmt-cluster --endpoint https://k8s.example.com[:port]

    # Create a TKG management cluster context using kubeconfig path and context
    tanzu context create mgmt-cluster --kubeconfig path/to/kubeconfig --kubecontext kubecontext

    # Create a TKG management cluster context by using the provided CA Bundle for TLS verification:
    tanzu context create mgmt-cluster --endpoint https://k8s.example.com[:port] --endpoint-ca-certificate /path/to/ca/ca-cert

    # Create a TKG management cluster context by explicit request to skip TLS verification, which is insecure:
    tanzu context create mgmt-cluster --endpoint https://k8s.example.com[:port] --insecure-skip-tls-verify

    # Create a TKG management cluster context using default kubeconfig path and a kubeconfig context
    tanzu context create mgmt-cluster --kubecontext kubecontext

    # Create a TMC(mission-control) context using endpoint and type
    tanzu context create mytmc --endpoint tmc.example.com:443 --type tmc

    # Create an Tanzu context with the default endpoint (--type is not necessary for the default endpoint)
    tanzu context create mytanzu --endpoint https://api.tanzu.cloud.vmware.com

    # Create an Tanzu context (--type is needed for a non-default endpoint)
    tanzu context create mytanzu --endpoint https://non-default.tanzu.endpoint.com --type tanzu

    # Create an Tanzu context by using the provided CA Bundle for TLS verification:
    tanzu context create mytanzu --endpoint https://api.tanzu.cloud.vmware.com  --endpoint-ca-certificate /path/to/ca/ca-cert

    # Create an Tanzu context but skipping TLS verification (this is insecure):
    tanzu context create mytanzu --endpoint https://api.tanzu.cloud.vmware.com --insecure-skip-tls-verify

    Note: The "tanzu" context type is being released to provide advance support for the development
    and release of new services (and CLI plugins) which extend and combine features provided by
    individual tanzu components.

    Notes:
    1. TMC context: To create Mission Control (TMC) context an API Key is required. It can be provided using the
       TANZU_API_TOKEN environment variable or entered during context creation.
    2. Tanzu context: To create Tanzu context an API Key is optional. If provided using the TANZU_API_TOKEN environment
       variable, it will be used. Otherwise, the CLI will attempt to log in interactively to the user's default Cloud Services
       organization. You can override or choose a custom organization by setting the TANZU_CLI_CLOUD_SERVICES_ORGANIZATION_ID
       environment variable with the custom organization ID value. More information regarding organizations in Cloud Services
       and how to obtain the organization ID can be found at
       https://docs.vmware.com/en/VMware-Cloud-services/services/Using-VMware-Cloud-Services/GUID-CF9E9318-B811-48CF-8499-9419997DC1F8.html

    [*] : Users have two options to create a kubernetes cluster context. They can choose the control
    plane option by providing 'endpoint', or use the kubeconfig for the cluster by providing
    'kubeconfig' and 'context'. If only '--context' is set and '--kubeconfig' is not, the
    $KUBECONFIG env variable will be used and, if the $KUBECONFIG env is also not set, the default
    kubeconfig file ($HOME/.kube/config) will be used.

Flags:
      --endpoint string                  endpoint to create a context for
      --endpoint-ca-certificate string   path to the endpoint public certificate
  -h, --help                             help for create
      --insecure-skip-tls-verify         skip endpoint's TLS certificate verification
      --kubeconfig string                path to the kubeconfig file; valid only if user doesn't choose 'endpoint' option.(See [*])
      --kubecontext string               the context in the kubeconfig to use; valid only if user doesn't choose 'endpoint' option.(See [*])
  -t, --type string                      type of context to create (kubernetes[k8s]/mission-control[tmc]/tanzu)

Release note

Additional information

Special notes for your reviewer

[vuil]

lgtm, some rewording suggestions