Allow multiple management planes

[aphralG]

Proposed changes

Add Auxiliary Command Server block to agent config.
Modified Command plugin to take a command server type so two can be created one for each Management plane
Added CommandServerType to context for management plane sepcific messages "command" or "auxiliary"

auxiliary_command:
    server: 
        host: "second.management.plane"
        port: 9999
    auth: 
        token: "1234"
        tokenpath: "path/to/my_token"
    tls: 
        cert: "some.cert"
        key: "some.key"
        ca: "some.ca"
        skip_verify: false
        server_name: "server-name"

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• I have run make install-tools and have attached any dependency changes to this pull request
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• If applicable, I have updated any relevant documentation (README.md)
• If applicable, I have tested my cross-platform changes on Ubuntu 22, Redhat 8, SUSE 15 and FreeBSD 13

[sean-breen]

Can you move this to the top near the ServerType declaration?

[aphralG]

I've moved all the SeverType code into the model package in server.go

[sean-breen]

Should this be addAuxiliaryCommandPlugin?

[aphralG]

No, the read only file plugin is added to this function in the next PR