Add backup config management to flexctl

[ndarilek]

This adds a flexctl backup config command.

root@5683596bd029d8:/# flexctl backup config help                                                                       
Manage backup configuration                                                                                             
                                                                                                                        
Usage:                                                                                                                  
  flexctl backup config [command]                                                                                       
                                                                                                                        
Available Commands:                                                                                                     
  show        Show current configuration                                                                                
  update      Update configuration                                                                                      
                                                                                                                        
Flags:                                                                                                                  
  -h, --help   help for config                                                                                          
                                                                                                                        
Use "flexctl backup config [command] --help" for more information about a command.                                      
root@5683596bd029d8:/# flexctl backup config show                                                                       
  ArchiveTimeout = 60s                                                                                                  
  RecoveryWindow = 7d                                                                                                   
  FullBackupFrequency = 24h                                                                                             
  MinimumRedundancy = 5                                                                                                 
root@5683596bd029d8:/# flexctl backup config update                                                                     
At least one flag must be specified.                                                                                    
root@5683596bd029d8:/# flexctl backup config update --minimum-redundancy foo                                            
error updating configuration: invalid value for minimum_redundancy: foo                                                 
root@5683596bd029d8:/# flexctl backup config update --minimum-redundancy 3                                              
Updated                                                                                                                 
A restart is required for these changes to take effect.                                                                 
root@5683596bd029d8:/# flexctl backup config show                                                                       
  ArchiveTimeout = 60s                                                                                                  
  RecoveryWindow = 7d                                                                                                   
  FullBackupFrequency = 24h                                                                                             
  MinimumRedundancy = 3                                                                                                 

[davissp14]

Awesome work with this! Just a few notes.

[davissp14]

To future proof this, we could consider just pretty printing the json output. However, I think this is totally fine for now.

[ndarilek]

I went back and forth on this but came to the same conclusion. If we make it more unwieldy, I'm happy to switch it later, or if you think we should do it now then I can.

[ndarilek]

All feedback should be addressed. Please let me know if I missed anything, and please make any suggestions for the command structure since I'm going to mirror it under fly pg and don't want to circle back and change it later. :)

Thanks.

[davissp14]

Looks good!