[REQ][php-slim4] Partial generation support

[ybelenko]

Is your feature request related to a problem? Please describe.

There are apis, models, apiTests, modelTests global properties to exclude some parts of application.

Describe the solution you'd like

• When both apiTests=false AND modelTests=false
  • Exclude phpunit.xml.dist from generation
  • Remove phpunit package from composer.json
  • Remove test, test-apis, test-models scripts from composer.json
  • Remove ## Tests section from README.md
• When apiTests=false
  • Remove Apis testsuite from phpunit.xml.dist
  • Remove test-apis script from composer.json
  • Remove composer test-apis command from README.md
• When modelTests=false
  • Exclude BaseModelTest.php from generation
  • Remove Models testsuite from phpunit.xml.dist
  • Remove test-models script from composer.json
  • Remove composer test-models command from README.md

Describe alternatives you've considered

Additional context