Added new validation for new ViewModel dialog

[bohdan-harniuk]

Description (*)
This PR adds validation through annotations to the new ViewModel dialogue. Related issue: #302
I've removed requested validator: com.magento.idea.magento2plugin.actions.generation.dialog.validator.NewViewModelValidator

There were 4 validation rules on top of the view model name field and 2 on top of the view model parent dir field.
All validation rules transferred to the new validation principle successfully, without adding new validation rules:

View model name field - Not empty rule:

View model name field - Should be valid PHP Class rule:

View model name field - Should contains alphanumerical characters rule:

View model name field - Should starts with a number or capital letter rule:

View model parent dir field - Not empty rule:

View model parent dir field - Should has valid directory name rule:

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with integration/functional tests (if applicable)
• All automated tests passed successfully (all builds are green)