Drush 10 command support

@andypost

1. Non-zero exit-code will definitly be useful for CI job to fail
2. config:inspect looks good to me !

I tested your patch @Andypost (#2) and it seems to work just great !

/var/www/html $ drush config:inspect --help
Inspect config for schema errors.

Examples:
  drush config:inspect          Inspect whole config for schema errors.                    
  drush config:inspect --detail Inspect whole config for schema errors but details errors. 

Arguments:
  [key] (Optional) Configuration key. 

Options:
  --only-error            Display only errors.                                                                                     
  --detail                Show detailed errors.                                                                                    
  --skip-keys[=SKIP-KEYS] Configuration keys to skip.                                                                              
  --format=FORMAT         Format the result data. Available formats:                                                               
                          csv,json,list,null,php,print-r,sections,string,table,tsv,var_dump,var_export,xml,yaml [default: "table"] 
  --fields=FIELDS         Available fields: Key (key), Status (status) [default: "key,status"]                                     
  --field=FIELD           Select just one field, and force format to 'string'.                                                     

Topics:
  drush topic docs:output-formats-filters Output formatters and filters: how to control the output produced by Drush commands 

Aliases: inspect_config

/var/www/html $ drush config:inspect --only-error
 ----- -------- 
  Key   Status  
 ----- -------- 

/srv $ drush en config_inspector
 [success] Successfully enabled: config_inspector

/srv $ drush config:inspect --detail --only-error
 ------------------------------ ---------------- 
  Key                            Status          
 ------------------------------ ---------------- 
  automated_cron.settings:data   missing schema  
 ------------------------------ ---------------- 

I think it would be great though to make it fully silent when no error, to avoid verbose in CI logs.
What do you think ?

@andypost, you are right, empty header is common accross drush commands

Fortunately --format=string option is useful to only print result without header
For readers, it's possible to print only errors list without any header usingdrush config:inspect --only-error --format=string

Btw, I tested last patch from #7 and it seems working all fine !