Unexport the builder and bake stub command

[Benehiko]

This patch unexports the builder and bake stub command and it adds
deprecation notices on the exported functions.

It also registers the commands using the new cli/internal/commands
package when the init function executes.

- What I did

- How I did it

- How to verify it

- Human readable description for the release notes

Go SDK: cli/command/builder: deprecate `NewBuilderCommand` and `NewBakeStubCommand`. These functions will be removed in the next release.

- A picture of a cute animal (not mandatory but encouraged)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 10 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
cli/command/builder/cmd.go	0.00%	8 Missing ⚠️
cli/command/commands/commands.go	0.00%	2 Missing ⚠️

📢 Thoughts on this report? Let us know!

[thaJeztah]

LGTM

[thaJeztah]

For the changelog / release-notes, we should probably make it something more to the point, like;

Go SDK: cli/command/builder: deprecate `NewBuilderCommand` and `NewBakeStubCommand`. These functions will be removed in the next release.

Ultimately, for users of this code as a dependency, that's the part that matters, but we can touch-up those later as well.

[Benehiko]

For the changelog / release-notes, we should probably make it something more to the point, like;

Go SDK: cli/command/builder: deprecate `NewBuilderCommand` and `NewBakeStubCommand`. These functions will be removed in the next release.

Ultimately, for users of this code as a dependency, that's the part that matters, but we can touch-up those later as well.

Okay, let me update the changelog description

[thaJeztah]

We'll probably need to rewrite some to a single large release-note, outlining that the release has many functions that were meant for internal use deprecated as part of our migration towards go modules (and people to contact us / open a ticket if there's anything deprecated that was essential to them).

For most of the things we deprecated I checked if I could find external users, and for most that was not the case (or only used in archived projects), so I don't expect many to be impacted.

[thaJeztah]

We'll probably need to rewrite some to a single large release-note

oh! to be clear; that's not for this PR, but more a "general" note 😅 (in case my comment was ambiguous)