Add artisan make:page command

[Gummibeer]

blocked by spatie/sheets#44

The package should provide a make:page command to simplify the process to create a new page.

The command should create the markdown file including YAML frontmatter head and an optional page data class.

• The make command should only work if the default filesystem repository is used in the sheet collection
• It should use the filesystem of the sheet repository
• It should add the page data class to the YAML frontmatter
• The default namespace for the page data class is App\Pages
• It should accept sheet collection and path as arguments
• The path should be possible with(out) extension
• It should use stub files to generate the files