Migrate enterprise commands to upbound

[hasheddan]

Description of your changes

Migrates all enterprise commands to instead fall under the upbound subcommands. Minor terminology updates are made in flag descriptions as well.

Signed-off-by: hasheddan georgedanielmangum@gmail.com

I have:

• [x] Read and followed Upbound's contribution process.
• [x] Run make reviewable to ensure this PR is ready for review.
• [ ] Added backport release-x.y labels to auto-backport this PR, as appropriate.

How has this code been tested

Verified that up upbound install / up upbound upgrade / up upbound uninstall function properly.