Provide a script for installing the CLI from the archive files we publish as a part of releases

[zjs]

Describe the feature request

As a user, I should be able to run a script that performs the multi-step process of installing the CLI:

• download and untar the appropriate tanzu-framework-(OS)-(ARCH).tar
• cd to the tar destination directory:
• move/copy core/v0.1.0/tanzu_core-(OS)-(ARCH) into somewhere in your PATH and rename it tanzu
• export TANZU_CLI_NO_INIT=true
• tanzu plugin install --local ./ all
• tanzu plugin list show the following plugins installed: "login", "pinniped-auth", "cluster", "management-cluster", "kubernetes-release", "package"

Community Edition includes scripts that accomplish this:

• https://github.com/vmware-tanzu/community-edition/blob/main/hack/install.bat
• https://github.com/vmware-tanzu/community-edition/blob/main/hack/install.sh

Describe alternatives you've considered

We should also find a better way to distribute the core CLI binary (#3) and provide an API for CLI plugin discovery (#74). However, this is intended as a stop-gap until that's available.

Affected product area (please put an X in all that apply)

• [ ] APIs
• [ ] Addons
• [x] CLI
• [x] Docs
• [x] Installation
• [ ] Plugin
• [ ] Security
• [ ] Test and Release
• [ ] User Experience

[navidshaikh]

Not fixed completely, the install scripts in #1157 are only used for validation and not being published part of the released artifacts. Now we've a plugin discover feature as well, the install scripts need to be designed to work with available plugin installation methods.