[FEATURE] Replace custom code generation with nette/php-generator

[kimpepper]

Is your feature request related to a problem?

The custom code to generate classes and methods is fragile and limited. We should consider nette/php-generator as an alternative as it provides a clean API for generating code.

What solution would you like?

Replace custom code generation scripts with nette/php-generator.

What alternatives have you considered?

Do you have any additional context?