feat: BETA loadbalancer service support

[displague]

Part of #411

(Used CPEM's LBaaS Go project as the base. Lots of cleanup ahead. )

This PR introduces the minimal subcommand support to start working with LoadBalancers. This PR does not include ports and pools, which can be added later.

TODO:

• Get LB
• List LB
• Detele LB
• Create Project LB
• Send debug transport to token exchange when debugging?
• Ensure command docs are correct
• Ensure requirement checks (required fields) are correct
• Ensure example commands are correct
• Ensure command is named "loadbalancer-beta"
• generate docs

[tylerauerbeck]

Just a few comments, but overall this looks like a great start!

[ctreatma]

Don't know that it would add much here, but if we had a spec for iam.metalcrtl.io we could use a generated client.

[displague]

cc @tylerauerbeck

[ctreatma]

One thing to consider here: if LBaaS has its own generated client that sits next to the metal client in equinix-sdk-go, with its own spec and its own API endpoint, that may indicate that LBaaS CLI commands should go alongside Metal CLI commands in a broader-scoped Equinix CLI (eqx? eqix? the-equinix-cli?) rather than directly in here.

[cprivitere]

Merged in latest updates and tested create/get/delete commands to verify they work.

[cprivitere]

One thing to consider here: if LBaaS has its own generated client that sits next to the metal client in equinix-sdk-go, with its own spec and its own API endpoint, that may indicate that LBaaS CLI commands should go alongside Metal CLI commands in a broader-scoped Equinix CLI (eqx? eqix? the-equinix-cli?) rather than directly in here.

I'm all for dropping metal-cli and making eq-cli or whatever.