Check for existing Tanzu Builder and use if there

[codegold79]

Description

Although it's not the recommended way to download and use Tanzu CLI Plugin Builder, provide a direct way to obtain the builder binary and use it. Bypass using Tanzu CLI altogether.

Fixes #108

Change Details

Check all that apply:

• New feature
• Bug fix
• Non-code change
• Non-breaking change
• Breaking change
• Requires a documentation change

Release Note

Allow for existing Tanzu Builder instead of installing it via Tanzu CLI

How Has This Been Tested?

Describe any testing done to verify changes. Provide enough detail that tests can be reproduced.

I built and published the codegen and featuregate plugins in the Tanzu Framework repository on my local machine.

Checklist:

• My code follows the Contribution and Style guidelines of this project
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes
• I have added test details that prove my fix is effective or that my feature works

[avi-08]

LGTM

[yharish991]

LGTM

[codegold79]

@yharish991, @avi-08 , I had to re-request review because I added a commit that put the tanzu-builder into a new directory, tanzu-cli.