Add retention settings to repo create command

[brads-au]

This change:

• Adds 4 flags to the repos create command. This allows the user to set a description, retention based on time, retention based on ingest and retention based on storage at repository creation time.

Example:

$ humioctl repos create newRepo1 --retention-time 72 --retention-ingest 130 --retention-storage 250 --description "Repo with retention settings"

$ humioctl repos show newRepo1
                        ID | mvVSvk4VVjoVZ9ToloNANTpj      
                      Name | newRepo1                      
               Description | Repo with retention settings  
                Space Used | 0 B                           
   Ingest Retention (Size) | 130.0 GB                      
  Storage Retention (Size) | 250.0 GB                      
          Retention (Days) | 72                            
      S3 Archiving Enabled | false                         
       S3 Archiving Bucket |                               
       S3 Archiving Region |                               
       S3 Archiving Format |                               
          Automatic Search | true