Move composer.json validate of sub-packages to GitHub Actions

[glensc]

Example failure job output (2 packages):

[...]
Error: "packages/zend-acl/composer.json" does not contain valid JSON
Parse error on line 8:
...: ">=5.3.3"        "zf1s/zend-exception...
---------------------^
Expected one of: 'EOF', '}', ':', ',', ']'
                                                                 
  [Seld\JsonLint\ParsingException]                               
  "packages/zend-acl/composer.json" does not contain valid JSON  
  Parse error on line 8:                                         
  ...: ">=5.3.3"        "zf1s/zend-exception...                  
  ---------------------^                                         
  Expected one of: 'EOF', '}', ':', ',', ']'                     
                                                                 

packages/zend-amf/composer.json is valid
packages/zend-application/composer.json is valid
packages/zend-auth/composer.json is valid
[...]
packages/zend-service-twitter/composer.json is valid
packages/zend-service-windowsazure/composer.json is valid

Error: "packages/zend-service-yahoo/composer.json" does not contain valid JSON
Parse error on line 20:
...l adapters"        "zf1s/zend-validate"
---------------------^
Expected one of: 'EOF', '}', ':', ',', ']'
                                                                           
  [Seld\JsonLint\ParsingException]                                         
  "packages/zend-service-yahoo/composer.json" does not contain valid JSON  
  Parse error on line 20:                                                  
  ...l adapters"        "zf1s/zend-validate"                               
  ---------------------^                                                   
  Expected one of: 'EOF', '}', ':', ',', ']'                               
                                                                           

packages/zend-service/composer.json is valid
packages/zend-session/composer.json is valid
packages/zend-soap/composer.json is valid
[...]
packages/zend-xml/composer.json is valid
packages/zend-xmlrpc/composer.json is valid
Error: Process completed with exit code 1.

• Origin: https://github.com/zf1s/zf1/runs/1583880760?check_suite_focus=true

[falkenhawk]

adding xdebug is not relevant for the scope of this PR, is it?

[glensc]

details are in the commit message.

[falkenhawk]

Thank you @glensc for your contribution!